[5] The town economy has historically rested on farming, ranching and oil production.

[5] According to the American Oil & Gas Historical Society, Edward Byrd, whose wife was a Cherokee woman, discovered oil seeps in 1882 southwest Chelsea, which was then part of the Cherokee Nation in Indian Territory.

He apparently took no action to exploit his discovery until 1887, when he and William B. Linn, a Pennsylvanian, and a group of investors from Kansas organized the United States Oil and Gas Company (USOGC).

The company subsequently leased drilling rights from the Cherokee Nation on 100,000 acres (400 km2) of land lying west of Chelsea between the St. Louis and San Francisco Railroad and the Verdigris River.

The well began producing a half barrel of good-quality crude per day from a depth of only 36 feet (11 m).

Although USOGC drilled ten other wells on its lease in the next two years, the total production was said to be only 12 barrels, economically insignificant, after which the company ceased operating.

Significant production dropped after 1916 and the oil companies stopped work in this field shortly after.

[5] According to the United States Census Bureau, the city has a total area of 1.7 square miles (4.4 km2), all land.

In 1998 the Chelsea High School boys track team won the state championship.

In 2007 the Chelsea High School Varsity cheerleading squad won the state championship.

Also in 2007 the Chelsea High School Softball team won state championship.