Vital Statistics and Demographics


Description of Washington County

County Seat: Weiser
Population: 10,021 (2014)
Area: 943,133

Washington County Information

The 9th Territorial Legislature of Idaho passed an act in 1879 creating the 11th County of Idaho from the southwestern part of Idaho County and the northern part of Ada County. The new County was named Washington in honor of the First President of the United States.

The area embraced that territory now included in Washington and Adams Counties. Weiser Bridge (today known as Weiser) was designated as the County seat. Adams County was created from the north part of Washington County in 1911.

Washington County now has 1,482 square miles and is 20th in size among Idaho’s 44 counties.

The area was first visited by white men in 1811, when Wilson Price Hunt and McDonald McKenzie, with four companions, passed through on the way to Astoria. In 1818, they came back with a crew of trappers. They spent some time catching beaver along the Weiser River. (Named after Peter Weiser, a member of the Lewis and Clark party). At the confluence of Weiser and Snake rivers in December 1811, the parties of Wilson Price Hunt and Ramsey Crooks were reunited, after they had traveled across Idaho on opposite sides of the Snake River.

Stopped by the Seven Devils Mountains, they both turned back to the Weiser River at about the same time. Hunt’s party built “bull boats” to cross the Snake River in order that the two groups might continue the trip together. They secured a Snake Indian to guide them the remainder of the way to the Columbia River. Hunt had been commissioned by John Jacob Astor to make an overland trip from St. Louis to the mouth of the Columbia River, in search of suitable locations for the establishment of a number of fur trading posts. It was on this trip that he gained the distinction of being the first white man to lead an expedition through southern Idaho. He and his men were the first to pass over the route later known as the Oregon Trail.

In 1863 the Idaho Territorial Legislature granted a license to operate a ferry to R.P. Olds, across the Snake River 10 miles below the mouth of the Weiser River. The crossing was known as Oldsferry.

Three forts were constructed in the vicinity of Weiser : The first on Hull Hill with Sol Jefferies as captain; the second on Mann Creek, called Sailing Fort, with John Sailing as captain; the third, Galloway Fort on the Weiser River, four miles east of Weiser.

In the spring of 1866, a company started what they called a “fast freight liner” from Umatilla to Oldsferry. It featured the steamboat “Shoshone”, built to operate between Weiser and a point on the Snake River midway between Boise and Silver City. It operated profitably until a stage line from Kelton, Utah to Boise City took the business.

In 1869, John Cuddy established the first flour mill in Washington County. In 1884, the Oregon Short Line (now known as the Union Pacific Railroad) reached Weiser. In 1899, the second railroad come, the P&IN RR was built in the Weiser River Valley from Weiser to Meadows Valley. Galloway became the first postmaster. Not long thereafter, Robert Moreland set up a gristmill, and by 1870 a settlement had taken form. Weiser Bridge was the original destination of the hamlet, but as it grew the name “Bridge” was dropped and it became known as “Weiser City.” The first newspaper was started in the summer of 1882.

In 1887, Weiser City became incorporated as a village and the word “City” was dropped. The railroad depot was located west of the original town site about a mile. The “new town,” as it soon became known, was started and the original town site came to be called “the old town.” In June of 1890, a disastrous fire burned down a large part of the original business center and the newer town site began to get the upper hand.

In 1904, a bridge was built across the Snake River.

Washington County Population

1970 1980 1990 1997
7,633 8,803 8,550 10,090


Population Per Square Mile

1970 1980 1990 1997
5.2 6.1 5.9 6.9


Land Ownership in Acres

Federal Land State Land Private Land County Land Municipal Land
345,844 72,473 510,664 2,920 195

Total Acres 932,096

Land Use

Urban Land Agricultural Range land Forest Water
3,500 134,000 706,000 92,700 12,200