My Question IS? Why did the U. S. Army suddenly spend $50,000 to build (six) iron bridges on June 12, 1858 in Indian Territory, on a wagon road from Fort Smith into Indian Territory, of all places?? Maybe these were some of the reasons:
TEXAS in 1858
Texas Gov. H. R. Runnels and Gen. Sam Houston appealed to the federal government to move all of the Indians of Texas’s Brazos Indian Reserve to Indian Territory as soon as possible.
Texas governor assigns Major Robert Simpson Neighbors, now Texas Indian Superintendent of Indian Affairs, the task of getting all Reserve Indians safely moved out and Reserve closed. On March 29, 1858, Major Neighbors recommended the abandonment of the Comanche Reservation and the Brazos Reservation and removal of all the Texas Reserve's Indians to Indian Territory. [Orders for their complete removal were not issued until June 11, 1859.]
https://www.tshaonline.org/handbook/entries/neighbors-robert-simpson
U.S. ARMY in 1858
William H. Emory was a major in the First Cavalry of U. S. Army when he came from Washington, D. C. to Indian Territory in 1858 as new commander at Forts Washita and Arbuckle. Emory's orders were simple but difficult. His command was expected to stop the Comanche, Kiowa, and Cheyenne in the Wichita Mountains from raiding the settlements in Texas and the Chickasaw and Choctaw in Indian Territory. Major Emory arrived at Fort Arbuckle to find the post in poor state. Buildings were dilapidated, and his troops lacked proper clothes, food supplies, and ordinance stores. As he tried to stabilize the facility, he was ordered (probably by Gen. David Twiggs, commander of Department of Texas in San Antonio) to construct another post further west to protect Texas tribes likely to be relocated soon to the Leased District in Indian Territory.
L. David Norris, “Emory, William Hemsley,” The Encyclopedia of Oklahoma History and Culture, https://www.okhistory.org/publications/enc/entry.php?entry=EM001.
USA & BIA in 1858
May 8, 1858 "General Orders, No. 4," from the "Head-quarters of the U. S. Army’s Department of Florida," announced that the Seminole War was closed. Moreover, Billy Bowlegs-a remaining Seminole Chief had been persuaded by BIA Indian Agent Elias Rector (and lots of U.S. dollars) to end the 3rd Seminole War in early May 1858 and leave South Florida for Indian Territory and the new Seminole homelands west of the Creek Nation. Bowlegs and 113 Seminoles left Florida and arrived by steamer in New Orleans on May 14, 1858. On May 21, 1858, his Seminole group left New Orleans on the steamer Quapaw for Fort Smith, Arkansas to join the new Seminole Nation in western Indian Territory.
https://fcit.usf.edu/florida/docs/b/bowlegs.htm
https://www.worthpoint.com/worthopedia/12-1858-harpers-weekly-seminole-1982823263
https://www.seminolenationmuseum.org/history/seminole-nation/into-the-west/
RESULTS
June 12, 1858 U. S. Congress passes U.S Army Appropriations Bill which contained $50,000 for the constructions of bridges and the improvement of stream crossings on the road on or near the 35-th parallel from Fort Smith, Arkansas to Albuquerque, NMT.
See this appropriation on p. 336 of U.S. Statutes at Large, Volume 11, p. 809, found in Google Books at:
https://books.google.com/books?id=7F82AQAAMAAJ&pg=PA809&dq=US+Army+Quartermaster+Fort+Smith+Iron+Bridge&hl=en&sa=X&ved=0ahUKEwifqY7Hjq3eAhUCVa0KHfwDB34Q6AEIRDAF#v=onepage&q=US%20Army%20Quartermaster%20Fort%20Smith%20Iron%20Bridge&f=false
1859
Texas’ Brazos Indian Reserve was abandoned on July 31, 1859. The two Indian Reserve groups, while moving north, were consolidated at the Red River, and on September 1 Major Neighbors, also serving as Superintendent of Indian Affairs in Texas, delivered them to Indian agency officials (including Elias Rector and associates) at Wichita Agency in Indian Territory. Neighbors would be assassinated by a disgruntled Texan on his return trip to Fort Belknap, Texas, at Fort Belknap on September 14, 1859.
Elias Rector soon decides to camp the Texas Reserve Indians along Cobb Creek and Washita River near the site of a new U. S. Army post Major William H. Emory has decided (jointly with Rector) to build on high ground just east of Cobb Creek and north of the Washita River.
Fort Cobb is opened on October 1, 1859 with 2 companies of 1st Cavalry and 1 company of 1st Infantry, USA.
Elias Rector is soon put in charge, as Superintendent, of a new Southern Agency of Bureau of Indian Affairs, which now included Texas, with his headquarters in Fort Smith, his home town.
Major William H. Emory is promoted to Lieutenant Colonel in command of three forts in Indian Territory: Forts Arbuckle, Cobb and Washita, with his command headquarters also in Fort Smith. Note: Fort Gibson (1857) and Fort Towson (1854) have been closed by the U.S. Army.
Beale Wagon Road will run from Fort Smith to Albuquerque, NMT. BWR will run thru new Seminole Nation and have a new 100-foot span Whipple bowstring iron bridge built across Little River leading into the new Seminole Nation's homeland located just west of the Creek Nation. Billy Bowlegs and John Jumper are both happy about having the new Iron Bridge Road opening soon.