World Waterfall Database

Illilouette Fall

Mariposa County, California, United States

Status: Cataloged
This waterfall has been surveyed in person by the World Waterfall Database.

Detailed Info

Illilouette Fall represents several polar extremes among the waterfalls in Yosemite Valley. On one hand, it is the most difficult of the major waterfalls in Yosemite Valley to properly view - requiring a moderate 4-mile hike from Glacier Point to reach - and as such is without question the least visited of the valley's major waterfalls. Though the falls can be distantly seen from the John Muir Trail between Happy Isles and the Vernal Falls bridge, the angle at which the falls drop makes it nearly invisible outside of the heavy flow season (and even then the profile view is that of a very narrow column of water). Proper up-close views of the falls require a head-on view from the rim of the gorge, where the true nature of the explosive falls can be appreciated as it thunders into the craggy canyon.

On the other hand, Illilouette Creek is the most voluminous and consistent tributary of the Merced River within Yosemite Valley and in following the falls are in full display for a longer period than any other waterfall in the valley, and do not run dry during the late summer months. We have not yet been able to find trustworthy data documenting the volume of water present in Illilouette Creek itself, but operating under the assumption that it's volume is - on average - greater than Yosemite Creek, we can infer based on the stream gauge on the Merced at the Happy Isles bridge that the springtime volume of Illilouette Creek can regularly eclipse 300 cubic feet per second, thanks to the 62-square mile drainage area.

The falls are commonly cited with a fall of 370 feet. In 2014 when we first were able to measure the falls in person we calculated a height of 381 feet, which seemed within the acceptable margin of error. Topographic models derived from one-meter lidar data however suggest a height of 364 feet (111 meters). While this too is close enough to the margin of error to be thought essentially accurate, it is also a more consistently reliable baseline than our field measurement was likely to be, so we will assume it to be the more accurate measurement until subsequent field measurements can confirm otherwise.

History and Naming

Illilouette Fall is the Official name of this waterfall.

Has also been known as:

  • Glacier Fall
  • South Canyon Fall
  • Too-lool-lo-we-ak

According to Lafayette Bunnell the Indian name for this waterfall was Too-lool-lo-we-ak, but suggested that it's literal interpretation was not appropriate for everyday use (what that translation is seems to have been lost in time). Bunnell proposed the name South Canyon Fall in following but this led to confusion in that the stream was thought to be the South Fork of the Merced River (which in actuality lies much further south). Josiah Whitney proposed the fall be called by its Indian name, which may have been bastardized into Illilouette, to which Bunnell then countered with the name Glacier Fall (for nearby Glacier Point) because the word "Illilouette" isn't an Indian word. In the end Whitney's suggested naming convention won out, but the real meaning of Illilouette remains unknown to this day.

Our Thoughts

Even though it's one of the five largest waterfalls in Yosemite Valley, Illilouette Fall doesn't quite have the same luster and visual impact as the others do - whether this is due to the fairly limited viewpoint looking down on the falls from above, or because you aren't afforded the same kind of grand, sweeping vistas of the falls as are available at Yosemite, Bridalveil or Nevada Falls is not immediately clear and is probably subject to individual interpretation. Don't take this as an indictment against the falls however, Illilouette Fall is still an extremely impressive waterfall, and for those who find themselves at Glacier Point looking for something to do, the hike down is certainly highly recommended, and all personal feelings aside it is still one of the best waterfalls in California.

Location & Directions

Coordinates:   Unknown
Elevation:   5800 feet
USGS Map:   Half Dome 7 1/2"

Illilouette Fall is best accessed from Glacier Point in Yosemite National Park - itself located about 30 circuitous miles from Yosemite Village via the Wawona Road and the Glacier Point Road (consult a park map when visiting). From the parking area find the large metal signs indicating the Panorama Trail which heads south from the trails heading to the viewpoints. The signs seem to have their distances a bit off, because one suggests the falls are 2-miles away, while the next says 1.6 miles. The actual distance is about 2 1/4 miles each way - stay left at the signed junction at the 1.7 mile mark. The viewpoint for the falls is unsigned but is fairly obvious. No guardrails are present at the viewpoint, and the ground is somewhat crumbly, so get no closer to the edge than your are comfortable with.

By The Numbers

The information presented in this table is meant to help identify and clarify the physical aspects of the waterfall for comparative purposes. While we try to ensure this information is as accurate as possible, sometimes it will prove necessary to either estimate or flat out guess at certain characteristics where either enough information isn't readily available, is not known, or we were not able to confirm a given trait upon surveying. This information may be changed at any given time to ensure accuracy.

Total Height

The Total Height listed for the waterfall represents the difference in elevation from the top of the uppermost drop, to the bottom of the lowermost drop of the waterfall, including all stretches of interstitial stream in between. Stream between two tiers of a waterfall is counted in its overall height regardless of whether or not that section of the stream would be legitimately considered a waterfall on its own right, were it to be isolated. Waterfalls with only one drop will of have the height of only the single drop listed here.

Tallest Drop

The Tallest Drop figure represents the height of the largest single drop within a multi-stepped waterfall. Waterfalls with only one drop will have the total height of the waterfall repeated here.

Num of Drops

The Number of Drops in a waterfall is a tally of the total number of distinct drops which make up the waterfall. Stretches of interstitial stream in between two or more distinct drops of a single waterfall are NOT considered to be distinct drops of the waterfall unless the section of stream in question would otherwise qualify as a waterfall were it to be isolated.

Avg Width

The Average Width of the waterfall represents the breadth of the waterfall from bank to bank under typical flow conditions, or if the waterfall has been Cataloged, under the conditions which it was most thoroughly surveyed. Often this number will be approximated because of a lack of approachability to many waterfalls. We often utilize Google Earth to measure the width (where imagery is of sufficient quality and resolution to allow it.

Maximum Width

Maximum Width represents a hypothetical measurement of roughly how wide a waterfall could get during peak streamflow or flood conditions. For smaller waterfalls, this figure will generally not differ much from the Average Width measurement, but for broader waterfalls - especially those that feature a crest that isn't constricted - this figure can at times be consideraby larger. Like the Average Width measurement, this measurement will take into account the difference in width at the top and bottom of the waterfall as much as possible, but will often be made based on the width of the crest of th falls alone.


The Pitch of a waterfall is an estimated - often very roughly - measure of the average slope or steepness of a waterfall. The Pitch figure only takes into account sections of stream which are actively falling. Pools or stretches of level stream in between two or more successive drops of the falls will not factor in this figure. As an example, a waterfall which features two truly free-falling leaps separated by several dozen yards of flat stream will have a Pitch of 90 degrees. Similarly, a waterfall with two drops separated by a pool, one with a true free-falling drop, and one with a Horsetail type fall will average the two, so while the Plunging drop has a Pitch of 90 degrees, if the Horsetail drop has a Pitch of 45 degrees, the total Pitch will be roughly 67 degrees.


The Run of a waterfall is a measurement representing the total linear distance on the ground between the top and bottom of a waterfall. This figure is not often easy to establish with a high degree of precision and as such will often be estimated. Waterfalls with a longer Run will usually either be less steep, often cascading type waterfalls, or will feature multiple steps separated by shorter stretches of a more gradual gradient streambed.


The system of classification of waterfall forms we use is a heavily modified derivative of the classifications outlined by Greg Plumb in his "Waterfall Lover's Guide to the Pacific Northwest" books. While plumb uses eight distnct forms, we wanted further granularity and opted to break down the hierarchy twofold: first based on the overall pitch of the waterfall, and then based on what shape the fall takes as it makes its descent. There are five primary Categories of falls in this system: Plunge, Horsetail, Steep Cascades, Shallow Cascades, and Rapids. Additional deliniation is then applied depending on characteristics such as the breadth of the falls, whether it splits into two or more channels, whether it falls in multiple successive drops, etc. For more information on our waterfall form classifications, see the Help page.


The watershed which a waterfall occurs within, if it is specified, will be based on the ultimate distributary watercourse to the ocean. For example, Washington's Palouse Falls occurs along the Palouse River - which is a tributary to the Snake River, which is itself a tributary to the Columbia River, which ultimately enters the Pacific Ocean, so Palouse Falls would then fall within the Columbia River watershed. Streams which empty directly into the ocean, or into a minor basin which then empties to the ocean will often have this field left blank.


The name of the watercourse which the waterfall occurs along. If the watercourse is not known to have an officially or colloquially recognized name, this field is left blank.

Avg Volume

The volume of water present in the stream at the location of the waterfall. This is often the most difficult figure to pin down because accurately measuring streamflow is not a simple process. We will rely on USGS data as much as possible, and attempt to take into account seasonal fluctuations in stream levels if possible. There is no guarantee that this figure will be accurate, and in cases where there is no USGS data to use, it may be a very, very rough estimate at best.


If known, the primary source of the watercourse which produces the waterfall will be listed here. This is helpful in determining whether a waterfall may flow more consistently during certain periods of the year - streams which originate in Springs, Lakes, or Glaciers will often flow more consistently throughout the year than those fueled by simply Runoff. The source of the stream may also be either unknown or undetermined.

Flow Consistency

A rough estimation of how many months out of the year the stream which produces the waterfall will actually hold water. The vast majority of waterfalls featured on this website will technically be truly perennial waterfalls (those that flow all year long), but some may see their flow dwindle greatly in the late summer months. This figure will not take into account the winter months when the waterfall may freeze, because in such cases the waterfall will very often be inaccessible. Entries which specify a Flow Consistncy of 12 Months should in general have an acceptable flow at any time of year (but may be better during certain periods - see below).

Best Flow

A general estimate of the best period of the year during which time the falls will be considered at optimal conditions, or flowing at their best. There may be variance within the range specified where the flow will be better or worse, but visiting at any time in the range specified (if available) will generally present the waterfall in its best light.



Cataloged Icon
Waterfalls which are Cataloged we have visited and surveyed in person. Statistical information should be quite accurate (for the most part), and exact measurements will often be available (information is not guaranteed to always be up to date). Detailed information, directions, and photographs will almost always be available.
Confirmed Icon
Confirmed Waterfalls are known to exist, should be relatively accurately mapped and geotagged, and the statistical information available will often be dependable. If height information is presented, it may be estimated but should be accurate. Directions will not likely be available.
Unconfirmed Icon
Unconfirmed Waterfalls are often marked on a published map, but we have yet to confirm the exact location and / or whether or not its stature is significant enough to qualify for listing in the database. Statistical information may be estimated and may be inaccurate. No directions.
Unknown Icon
Waterfalls marked as Unknown are either suspected to exist based on heresay or a hunch, or we have received unverified information suggesting a waterfall may exist near the location provided but cannot corroborate it in any way. Geodata may not be accurate, the location may not be known at all, and statistical information will be estimated and highly inaccurate.
Inundated Icon
Inundated Waterfalls have been submerged beneath lakes or reservoirs, usually a result of impoundment of a river behind a dam, and most often no longer functionally exist (there may be rare exceptions). We maintain records for these features out of historical importance.
Subterranean Icon
Though not common, some waterfalls can be found entirely underground within cave systems. Access to subterranean waterfalls can vary from easy via developed walkways to requiring a high level of extremely technical spelunking skill, including familiarity with ropework and a distinct lack of claustrophobia.
Disqualified Icon
Waterfalls which have been marked as Disqualified do not have the necessary stature or features to qualify as a legitimate waterfall according to our criteria. We will maintain records for entries with this status where the feature is well known and / or may have been historically referred to as a waterfall at some point in time.
Posted Icon
Posted Waterfalls are known to exist, and we may have a large amount of information associated with them, but are located on private property and are not legally accessible to the general public. Accessing waterfalls with this status should not be attempted without first being explicitly granted permission of the property owner.

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