They had allied with the Confederacy during the war and needed to make a new peace treaty with the United States afterward as a result.

In 1869, a post office (originally spelled Okmulkee) was established in the town, with Captain Frederick B. Severs appointed as the first postmaster.

[5][8] The Shawnee, Oklahoma and Missouri Coal and Railway (also later acquired by the Frisco) was built from Muskogee to Okmulgee in 1902-03, and lasted until abandoned in 1973.

Discovery of oil at nearby Morris in 1907[13] stimulated expansion of Okmulgee, and attracted several new industries to town.

[26] But decreasing oil production and lower prices, the coming of the Great Depression, and other factors caused the population to shrink to 17,097 by the 1930 census.

[29] According to the United States Census Bureau, the city has a total area of 33.8 square miles (33.2 km2), all of its land.

[5] In the 21st century, the most important business sectors in Okmulgee are: construction, retail trade, health care & social assistance, and accommodation & food services.

[5] The Okmulgee area's major employers include the Muscogee (Creek) Nation, Anchor Glass (plant is in Henryetta), Paccar Winch-Okmulgee, C.P.

Kelco US Inc., Honeywell's Callidus Technologies (facility is in Beggs),[33] East Central Electric Cooperative, Covington Aircraft, G&H Decoy (in Henryetta), and PolyVision.

[43] Other MCN facilities in town include the College of the Muscogee Nation, a tribal college primarily for students seeking careers in the tribal sector, located at 2170 Raven Circle;[44] One Fire Casino at 1901 Wood Dr;[45] and, the Claude A. Cox Omniplex, cattycornered across from the Tribal Complex off U.S. 75 and Loop 56, which includes the Muscogee Dome multipurpose recreation center and other festival grounds and facilities.

[56] Okmulgee Municipal Park, at W 20th St. & S Seminole Ave., features a bike trail, walking track, playground, and soccer field.

[61] In support of Okmulgee's downtown, an organization has been formed called Okmulgee Main Street, one of the various national Main Street programs that aim to reenergize their respective downtowns and commercial districts through preservation-based economic development and community revitalization.

[63] Among the downtown structures is the Orpheum Theater at 210 W 7th St, which opened as the Cook Opera House on August 23, 1920 with 1,200-seat capacity.

[65] The Orpheum's architecture, which is an elegant derivation of Spanish Baroque Revival, includes a colorful lobby which is the finest example in Oklahoma of the interior use of polychrome terra cotta.

[69] In 2012 the Muscogee (Creek) Nation purchased the Okmulgee Golf Club, also known as the Okmulgee Country Club, at 1400 S. Mission Street, an NRHP-listed location complete with the original 1920 golf course[70] and the 1925 clubhouse built using locally sourced limestone.

[80] At the festival in 1989, a record was set for what was then the largest pecan pie in the world, being 40’ in diameter and using over sixteen-and-a-half tons of ingredients.

[82] The Okmulgee County Fair is held annually (typically in September) at the Okmulgee County Fairgrounds, and includes commercial booths, exhibits, livestock shows, livestock judging, a horse show and cattle displays.

Okmulgee is in the 10-county region served by the KI BOIS Area Transit System ("KATS"), a low-cost public bus/van service established in 1983 to help communities, primarily in southeast Oklahoma, by providing access to Senior Citizen centers, groceries, medical services, and jobs.

[93] OHS Broadcast Media is an Official Okmulgee Public Schools site for all things Bulldog.

[94] KOKL, a/k/a The Brew, is a broadcast radio station in Okmulgee on FM 106.3 and AM 1240, playing classic hits of the 60’s, 70’s and 80’s.

[95] The pilot for the FX comedy series Reservation Dogs from filmmaker Sterlin Harjo, which concerns four Native American teens in rural Oklahoma, was shot in Okmulgee.

[96][97] Additional principal photography for the rest of Season One also occurred in Okmulgee, as well as Tulsa, Sand Springs, Beggs, Inola, and Terlton.

[101] In the Elmore Leonard novella “Comfort to the Enemy,” the parties stay in Okmulgee while visiting the POW camp.