All kinds! Road maps, geologic maps, soils maps, topographic and other maps showing physical features, political maps, bathymetric charts and many more covering all parts of the world and even other planets and star charts. The Valley Library is a federal depository library so we receive a lot of government maps, but we also purchase maps and atlases from publishing companies.
For the most part, very much like other materials in the library. Many of our maps have entries either in the online catalog or, in the case of older materials, in the Maps card catalog (3rd floor, Maps & Government Publications). These give call numbers and location information.
One of the most successful ways to search is to use the place name as the subject (city, county, country, region, national forest, river, etc.) with --Maps or --Road maps or some other map designator (you can find more in the Library of Congress Subject Headings books).
Sample subject heading searches:
Map of Eugene search: Eugene (Or.)--Maps
Road map for Lincoln County: Lincoln County (Or.)--Road map
Some of the more current Forest Service visitor maps are located in the Government Documents section on the 3rd floor under their SuDoc call number, starting with A 13.92/2: You may wish to search the online catalog by the name of the national forest you're interested in, to see where the latest map is located.
Many of OSU Libraries' historic and rare maps are located in the Special Collections and Archives Research Collection (SCARC) on the 5th floor. Finding aids have been created for most of them and can be seen on their website at http://scarc.library.oregonstate.edu/coll/maps.html along with information on how to access them. Most have a record in the online catalog, too, with a link to the finding aid.
The Maps collection atlases are on the 3rd floor, designated as Map Room Ref in the online catalog. There are also atlases in the general collection. Using the word atlas in your search should bring up most of them.
Right now, only atlases in the general collection--not the Map Room Ref atlases--can be checked out. Be sure to check the locations in the online catalog for individual titles, because sometimes a reference atlas also has a circulating copy in the general collection.
Most of our maps do circulate! Those that do not are primarily the various historic maps collections, Army Map Service maps and Sanborn Fire Insurance maps, as well as maps labeled "storage" which are usually over 30 years old and beginning to deteriorate (see Map Collections for more information). So generally speaking, if they aren't locked up then they probably can be checked out.
Yes, maps are checked out at the Circulation Desk on the second floor. They are circulated in map tubes. Please don't fold these maps (even if it looks like they used to be folded), but keep them rolled in the map tube when not in use. Be sure to return the tube with the maps!
Our checkout period is three weeks (with three renewal periods allowed) for every patron, regardless of his or her status (undergrad, grad, faculty, community patron, etc.).