If you’ve ever wanted a large old map of Columbia County, but didn’t want to shell out $300+ to buy one at auction, you’re in luck. The Library of Congress has a high-resolution scan of the 1858 Beers map which can be downloaded for free at this link.
To download the largest version, use the bottom-most file link on the left hand side. (This could in theory be printed as large as 20 feet square at 72 dpi, but would look better at about 40 inches square and 300 dpi.)
If you just want to inspect the map without downloading, the site also has a handy viewer that lets you zoom in to a specific part of the county.
Two of the more intriguing uses of these maps is either to identify who owned a historical house 160 years ago, or to find the sites of houses which have since been torn down... There are a lot of abandoned foundations out in them woods.
A shortcut to correlating old maps to new ones can be found at this astonishingly handy site, which overlays historic maps with current Google ones. (The example here uses an 1873 Beers map for Taghkanic.) Use the “slider” on the righthand side to change the old map’s opacity, revealing the underlying current one. By also clicking on the “Google Hybrid” button, you can see a satellite image, making it easier to see which 19th century house site lines up with present-day buildings.