Finding maps for land research
Use maps maps and more maps
Use the Atlas of Historical County Boundaries to see if the county was the same when he would have gotten his patent because it visually shows you what the state looked like at a given time.
Use the Libre Map Project to zero in on Township & Range or specific areas (slow to load but worth it)
PLAT MAPS
start with Google
"Yuma County" Colorado ~plat map
historic ~atlas "Bucks County" Pennsylvania
look at both the web results AND the image results view
large collections that have many plat maps:
If you have Ancestry they have a very large collection of plat maps here is the link
Historic Map Works Collection - they sell these maps but you can look at them without buying
Internet Archive
Library of Congress Map Collection
examples of some collections and guides for specific states
If they lived in a town don't forget to search for a city directory.