KMZs and other files showing the distribution of Lahontan Cutthroat are available from the download system.

Note:  Lahontan Cutts are officially listed as a "Threatened Species".  Nevada fishing regulations, however, generally treat the Lahontan like any other cold water game fish.  A few streams are closed to fishing (check Nevada regulations).  Please practice catch and release even where not required by state regulations.

Lahontan Cutts are a miracle.  They were originally native to a Lake Lahontan which, at the end of the last ice age (14,000 years ago), covered much of north-western Nevada and touched on eastern California. As the earth heated up, and the area grew increasingly dry, the "pluvial" lake shrank to individual rivers, streams, and lakes within the original basin, stranding individual pockets of Lahontan Cutts.  Even more remarkably, the trout adapted to their new conditions, becoming tolerant of higher temperatures and able to survive in streams which would partly dry-up during the peak of summer.

Historically, Lahontans inhabited both lakes and streams across their range.   The lacustrine trout could grow to enormous sizes (photos show early 20th century 'sports" showing-off 20 lbs. Lahontan cutts).  Unfortunately, most of the lakes were at some point stocked with Lake Trout, which dominated the cutts, and generally extirpated them.  Today, with rare exceptions, Lahontans survive only in the headwaters of streams, where intermittent flows or other barriers isolate them from exotic trout competitors (typically stocker-strain rainbows with which they will readily hybridize).

We provide 5 datasets to help you locate Lahontan Cutts, two of which are "range wide", and three of which are useful in a narrower range.

Four of the 5 datasets are illustrated in the photo above. All are available for download from the download system.

1. Range-wide basin data, which color codes for habitat quality, is from a KMZ published by the TU Conservation Success index. 
2. Range-wide streams with Lahontan populations (magenta streams) are rendered by a KMZ created by WildTroutStreams.com.  This geo-locates the principal populations identified in Appendix E of the 1995 recovery plan.  These represented all of the locations supporting Lahontans known at that time, including all of the "in basin" locations, plus some additional self-sustaining populations established in southern Oregon, northern California, and western Utah.  Surprisingly, there seems to be relatively little updated data about Lahontans since that report.
3. Oregon-wide data (orange streams - you can see a few in the image in southern Oregon) are from a dataset created by the ODFW and distributed via StreamNet.org.  It shows the range of Lahontan within the state of Oregon (in the photo, many are obscured by magenta lines, which have been rendered on top of the Oregon data).  If you're planning on fishing for Lahontans in Oregon, we suggest using this dataset, as it's somewhat more accurate than the dataset in #2.
4. Lahontan-compatible streams (cyan lines) across the Humboldt-Toiyabe National Forest.  This is probably the single largest land manager for Lahontan habitat (along with BLM and the Park Service).  This dataset, along with its companion, which indicates general trout habitat, does not seem to indicate actual populations, merely appropriate habitat.  Many of these streams are likely to support exotic trout instead of Lahontans.  Nevertheless, you may find a use for this data in combination with the other sources.

Finally, not shown on the main image, but very useful, is the dataset for Marys River and Maggie Creek sub-basins.  These are maps from a scientific study commissioned by the US Fish and Wildlife Service to perform genetic analysis (the Maggie Creek Map is shown on the left).  The thick, black segments illustrate where the researchers thought the Lahontan Cutts actually lived (following extended experience catching a bunch of fish to get DNA samples).  Some observations based on this and the other map (both of which are supplied as a Google Earth image overlay) impact how you should use any of this data.

• Lahontan populations are often highly localized.  Even within a listed stream, they seem to inhabit a relatively small segment of the water.
• One likely place to find them is in the headwaters, more or less as soon as the stream supports a year-round flow, and for a relatively short distance downstream.  A second likely place to find them is near stream junctions, if both support Lahontans.

My simple-minded fisherman's brain reduces that to "headwaters and junction pools".  It's probably not that simple, but it's where I'd start (mind you I'm sitting in NJ, and have never fished these streams, so consider the source before taking my advice).

If you haven't set up your "trout workstation", we urge you to download the NHD and Geonames layers.  The NHD layer will give you all of the stream names, their flow lines, and is color coded for year-round (blue) and intermittent flows (white lines).  Resident populations are almost certainly going to live in the reaches with permanent flow.

You can get a sneak preview of what you'll get with all of this data if you set it up in Google Earth in the last photo.  Scroll down below the photo if you'd like to read an explanation of what you're looking at.  This is showing roughly the area in the red box on the Maggie Creek map (you can just see the "on"  and border of the "Toro Canyon" box in the upper left).

The Google Earth display is extremely infomative, but can be confusing if you're looking at it for the first time.  Here's what you're seeing in this detail (from background to foreground):

1. The mountainous shading background comes from the Google Earth aerial imagery which is only partially visible through the green and yellow overlay.  You can turn off the overlay if you want to look at it in detail.
2. The green and yellow background tint comes from the TU CSI basin data.  A green basin means that TU's models reckon it's some of the best Lahontan habitat there is.  The basins are coded (best to worst) blue, green, yellow, orange, red, brown.  To my knowledge, CSI doesn't rate any Lahontan habitat blue, so green is as good as it gets right now.
3. The big purple splotch is a magnified view of the Maggie Creek map in the previous image, and indicates a resident trout population.  The gray background in the original map has been erased, and it's been geo-registered and overlaid on the Google Earth display.  We photoshopped the image so that the thickened areas indicating resident populations would be easier to see (purple) instead of the thickened black areas as on the original map.  The heavy, navy-blue lines are the stream lines from the same image overlay. 
4. The place names with colored highlights (e.g. Coyote Creek, colored blue to indicate a stream name, and Toro and Barber Canyons, highlighted green to indicate a land feature) come from the geonames layer (linked to a USGS server).  The stream running through Toro Canyon is too small to have its own name, so by convention it's called "Toro Canyon Creek".  Same with "Barber Canyon Creek".
5. The thin,  light blue lines are stream lines generated by the NHD KML (which connects Google Earth to another USGS database, containing the National Hydrology Database (NHD).  Note it's showing you a lot more detail than the other map.  The arrowheads show flow direction.  The gray circles with a dot indicate a spring source.  Note Barber Canyon Creek has three spring sources running together, but then the stream goes white.  This suggest the headwaters are year-round, but the creek dries at times just below the headwaters.  If we were exploring Barber Canyon Creek for fish, I wouldn't spend much time in the white segment.
6. The magenta line on top of the several of these streams is from the KMZ we prepared.  It indicates the stream is listed in the 1995 recovery plan as supporting a population of Lahontan cutts (though the whole stream is marked).  Note that the navy blue overlay, light blue NHD, and Magenta lines are all telling you different information about the same streams.  They don't align perfectly, but they're very close.

Put all together and you have an immensely informative set of information to help you find a place you wish to fish.