There isn't much information available on Tristate , probably since it was pretty insignificant and didn't last more than a year or two. It's location as a point for a ferry to cross the Colorado River from the nearby Arizona town of Katherine outlasted the town itself by at least a decade. Lucky, E Clampus Vitus managed to jot down a few notes for us.
In the early 1920s, the Katherine Mine on the Arizona side of the Colorado was in active operation. A small community known as Tristate was developed on the Nevada side of the river. It boasted it's own school district from 1921 through 1924. The Katherine, originally known as the Catherine, was found in 1900. The area was originally prospected in the 1860s, and by the turn of the century S. C. Bagg, a local teamster, located an outcrop which looked promising. When panned, it showed good color and Bagg claimed the site. Within the first three years, over 2,000 tons of ore was taken out of the mine. Between 1904 and 1910, the mine was worked on and off. After the 1915 Oatman mining boom started, new prospecting began in the Katherine area. Many of the new mines used Katherine in their names, to pick up the aura of the Katherine. Two communities, Tristate in Nevada and Katherine in Arizona, were built to accommodate the new miners and their families. Katherine boasted a post office from 1922 until 1929, while Tristate never did. The Katherine had been reopened in 1919, and operated nearly continuously until 1928. With the advent of the Great Depression in 1929, the Katherine Gold Mining Company declared bankruptcy and closed, as did most of the mines in the area. During the early to mid 1930s, the Katherine Mill operated on and off, as did the mine itself. With the advent of World War II, most of the gold mines in America were closed. In the Katherine's case, this occurred in 1943. The closers came about because gold was not a needed war metal. Rationing boards did not provide access to needed supplies, and miners were subject to being drafted. The Katherine, producer of nearly $2,000,000 in ore, was closed forever. The site of the 1920s Tristate, Nevada is now under Lake Mohave, and Katherine, Arizona's site is nearly gone as well. They live on only in the historical record.
-https://www.quehoposse.org/index.php/plaques/39-oasis-in-the-desert QuehoPosse E Clampus Vitus
Activity on the Arizona side of the Colorado River is what got Tristate going.
The movement [to locate claims] is particularly marked in the camp of Katherine, located about 35 miles from Kingman, and in the camp of Tristate, located about three miles from Katherine on the Nevada side of the Colorado River. Although it is in Nevada, Tristate draws on Kingman for supplies and is said to be to all intents and purposes a part of the mining industrial movement for which Kingman is the focusing point. The men behind Tristate are well known Nevada miners. The veins at Tristate are considered to be a continuation of the gold-bearing veins of the Katherine district, where, in a single mine-- the Katherine-- between three and four million dollars worth of ore has ben blocked out.
-Mohave County Miner, August 5, 1921
Folks got pretty excited about the whole deal
COUNTY OFFICIALS PAY VISIT TO NEW TOWN OF TRISTATE
This week Del Sherer, chairman of the board of supervisors, and other county officials paid a visit to the Katherine section to look over a proposed road from the end of the Katherine road to a point opposite Tristate, Nevada. The trip extended to Tristate, where they found considerable activity. There are several houses already built, more in the course of construction, a good boarding house and store. The store is operated by Mrs. E. S. Chafey, who has had a world of experience in new mining camps, having accompanied her husband into all the new excitements in Nevada and other states. The townsite has had a large amount of work done on it in the way of leveling the ground, clearing the streets of debris and building a road to a connection with the road from the Arrowhead Trail.
-Mohave County Miner, August 12, 1921
The usual promotions and bragging that were frequent any time they talked about new mining camps were no exception here.
Over at Tristate, where the outcroppings of gold of the Katherine mine have been located, things are booming and it looks like within a very short time a second Tia Juana will be in full blast. The ferry has been moved down from Searchlight to take care of traffic from Arizona into Tristate.
-Mohave County Miner, September 9, 1921
Los Angeles big shots bought in and tried to make a killing on lots 'n' such
TRISTATE TOWNSITE DEAL CONSUMATED AFTER OPENING
A deal was consummated this week whereby the town of Tristate was taken over by Los Angeles capital, C. W. Boris having been selected as the manager of the new organization. A large advertising fund has been appropriated and a selling campaign started at once. Though at this time there are more than two score buildings in the town it did not have its formal opening until last Saturday.
-Mohave County Miner, September 30, 1921
Got to have a big party.
OPENING AT TRISTATE PROVED BIG SUCCESS
Visitors From California, Arizona, and Nevada Enjoy Mining Camp Hospitality
A big crowd and a fine, old-fashioned, mining camp hospitality marked the opening celebration of the new town of Tristate, near the southern point of Clark county. The Pacific Standard airplane owned by H. H. Spencer, of Roger's Airport, Los Angeles, and piloted by H. Montee, made the flight from Vegas to Tristate in 1 hour 15 minutes and was kept busy carrying mining men who wished to look over the country.
-Las Vegas Age, October 1, 1921
By the Spring of 1922, Tristate was no longer "the nearest town," apparently.
Crossings may be made at the Katherine-Tristate Ferry, and a person is enabled to then continue his trip through Nevada points, Searchlight being the nearest town, if he desires.
-Mohave County Miner, April 28, 1922
Sure it was about gold mining, but in 1922 there were other ways to make a buck
GREAT GRIEF COMES TO MOHAVE BOOZE MAKERS
Yesterday federal officers working in conjunction with deputies from the sheriff's office went to Tristate and arrested WIlliam Clayton of Las Vegas. In Clayton's cabin the found a 10-gallon still and a 20-gallon still in operation, 12 gallons of whiskey and four 50-gallon barrels of mash. On Len Sneider's premises they found a 50-gallon still in full operation, 4 barrels of mash and 20 gallons of whiskey, along with a quart of liquor in Sneider's car which was confiscated. Sneider escaped. Tristate is a source of supply for Mohave county and on these grounds the arrests were made. The officers say that they expect to make other arrests in Tristate.
-The Coconino Sun, November 3, 1922
Obviously people were still living there in 1924.
CHARLES HERSCHMAN DROWNED IN WATERS OF COLRADO RIVER
The Colorado river has claimed another victim, Charles Hirschman, a veteran of the World War, losing his life in the murky waters, while trying to cross the stream late last Sunday evening. Herschman and three companions were ferrying their camp equipage across the river to Tristate, and had taken several loads. The boat overturned, throwing the men into the water.
-Mohave County Miner, November 24, 1922
Tristate Ferry operated as late as 1930, as UNLV has in its collection a coupon book from 1930.