Mountain man Jim Bridger wintered with Crow nomads near present-day Emigrant in 1844–45.

Hunting and trapping brought many men across this area during the first part of the 19th century, but by 1850 the beaver population had nearly disappeared.

By the late 1860s considerable traffic was also arriving (and departing) via the Yellowstone River, at an embarkation point in the Livingston area.

The group of 600 men encamped at Fort Howie, near the mouth of Shields River, five miles (8.0 km) east of present-day Livingston.

In 1868 an Indian agency (including a fortified structure) was established on the Crow Reservation, at Mission Creek, southeast of Livingston.

A ferry service to the fort was set up to cross the Yellowstone River, four miles (6.4 km) east of present-day Livingston.

In 1881 the Northern Pacific Railway entered Montana Territory and extended a line to Livingston (which by this time had 500 inhabitants) by November 22, 1882.

The local population continued to grow rapidly; by 1887 the territorial legislature had authorized a county and its government had been set into motion.

[6] The highest natural point in Montana, Granite Peak at 12,807 feet (3,904 m), is in Park County.

Voters in Park County tend to support the Republican Party candidate in national elections (79% since 1904).