How many soldiers in the west would the U.S. army be able to bring together in a short time, in 1853? I would also like to know similar numbers for Mexico (pre gadsden purchase.)
In Mexico? A couple of thousand maybe.
The US Army has 2 regiments of Dragoons, 1 regiment of Mounted Rifles, 8 regiments of Infantry, 4 regiments of "Artillery" (actually infantry) and 2 batteries (4 guns each). Dispositions were:
1st Dragoons: scattered around California
2nd Dragoons: Kansas
Mounted Rifles: Texas
1st Infantry: scattered along the Rio Grande
2nd Infantry: scattered throughout California, Nevada and Oregon
3rd Infantry: scattered through New Mexico territory
4th Infantry: scattered around California
5th Infantry: mainly at Ft McIntosh, Tx
6th Infantry: suppressing the Mormons in Utah territory
7th Infantry: Arkansas frontier
8th Infantry: scattered throughout Texas
1st Artillery: 1 battalion in Tx and 1 in Florida, Battery K (4 guns) in Texas
2nd Artillery: almost the entire regiment deploy as infantry in Florida (Company M would beremounted as Battery M in 1853-4)
3rd Artillery: B and L are infantry in Texas, C is a mounted battery in Indian Territory, the rest are out east at late in the year are mostly drowned whilst deploying to California
4th Artillery: Companies D and M are in Tx as infantry, the rest of the regiment is infantry in NE USA (HQ Baltimore)
So in Texas you have the Mounted Rifles, 1st, 5th and 8th Infantry, a composite infantry battalion of 1st, 3rd and 4th Artillery and a 4 gun field battery with 6 pdrs (Battery K, 1st US Artillery)- about 3,000 effectives in all.