I have just found several ancestors and am puzzling how to store the related images. I don't REALLY want to download/print all of it. The images are a nice way to see where families lived, especially in relation to siblings, parents, in-laws, etc. While census records can sometimes do that, they won't usually show you (for example) when two parcels of land back up against one another.
The other thing I was able to do with the maps was prove to myself (not without a shadow of doubt, but close) that I didn't just miss an ancestor in the census. I show this family in two censuses twenty years apart and with roughly the same neighbors, but was missing one census in the middle. It was a small town, so I have actually perused the whole town looking for them, not relying on the index at all. I couldn't find them. With the maps though, I was able to trace the census taker's approximate path through town... one that led him/her in a circle AROUND this family and several of their neighbors. Oh well.
I've also located a friend's current house on the map, discovering who owned it in 1867, shortly after we believe it was built. I was able to follow this up with a census search to see that family. Names around them appear nearby on the map as well, so I was reasonably certain that the family didn't just OWN the house, but also LIVED in it. My friends only just moved into the house, so its history is still a bit of a mystery. Hopefully, we'll be able to do a deed search in the future to find out more, but this will satisfy my curiosity for now.
The atlases also have lists in them of area "subscribers" who had prepurchased the books (just like Harry Potter books now!). Some of these are really useful, like the one I saw in Boone County, MO which lists where people's "origins" were. Occupations and addresses are frequently listed in either subscriber lists or in advertisements/directories. Pictures of homes and businesses are included in some of the atlases, but I haven't found any of my ancestors in those (yet?).
Oh, yes, and the maps might be useful if you are trying to figure out geography of an area, including roads, railroad stations, etc.
Here is some of what Ancestry.com says about this source:
Land ownership maps are portrayals of land purchased, granted, or inherited. They range in complexity from rough outlines of the boundaries of one tract of land to detailed county atlases showing every landowner at the time of compilation.
This database contains approximately 1,200 U.S. county land ownership atlases from the Library of Congress’ Geography and Maps division, covering the approximate years 1864-1918. Some photos of county officers, land owners, and buildings or homes are also included. Due to the quality of the microfilm on which these maps and photos were originally located, some of the images may not appear very clear.While city atlases served a specialized clientele, their rural counterparts, known as county landownership atlases, were a commercial enterprise promoted by subscription campaigns and directed to a wider audience. Based on the pre-Civil War production of wall-sized, single-sheet county landownership maps, atlases showing landownership developed into a popular atlas format starting in the 1860s in the northeastern United States, and expanding into the Midwestern states by the 1870s and 1880s. These commercially published atlases contain cadastral or landownership maps for the individual townships within a county. In addition, they often include county and township histories, personal and family biographies and portraits, and views of important buildings, residences, farms, or prized livestock. (Library of Congress. Geography and Maps: An Illustrated Guide. http://www.loc.gov/rr/geogmap/guide/gmilltoc.html.)