United States, Bureau of Land Management Tract Books, 1820-1908 on FamilySearch.org

This may not seem like a big deal, but it is a big deal. The United States, Bureau of Land Management Tract Books, 1820-1908 were just added to FamilySearch.org's Historical Record Collections. Quoting from the National Archives:

The land records that are generally of most interest to genealogists are the land entry case files. These are records that document the transfer of public lands from the U.S. Government to private ownership. 

There are over ten million such individual land transactions in the custody of the National Archives. These case files cover land entries in all 30 public land states.

These are the types of records that can establish the identity of ancestors. Here is a further explanation of what can be gleaned from these records:

Land case entry files can contain a wealth of genealogical and legal information. Depending upon the type and time period of the land entry, the case file may yield only a few facts already known to the researcher or it may present new insights about ancestors, family history, title, and land use issues. For example, the records may attest to the one's age, place of birth, citizenship, military service, literacy, and economic status, and may even include similar information about family members. But even the smallest case files can establish locations of land ownership or settlement and dates essential to utilize other resources at NARA, such as census, court, and military service and pension records.

What was added to FamilySearch.org is copies of the Tract Books. Here is the National Archives description of these records:

Tract Books:
There are also tract books available relating to the land entry case files. These are arranged by the legal description of the land: by township, range, section, etc. Tract books are divided into two geographical areas, Eastern States and Western States 

For the Western States, the tract books are located in the National Archives Building in Washington, DC. This includes the states of: Alaska, Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Utah, Washington, and Wyoming 

For the Eastern States, the Bureau of Land Management (BLM) has the tract books and patents. This includes the states of: Alabama, Arkansas, Florida, Illinois, Indiana, Iowa, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Ohio, and Wisconsin.

 Searching the Tract Book records, presently without an index, can be a daunting task, but would be worth the effort to determine the existence of a case file. The key to finding what you want to know is on this page of the FamilySearch.org Research Wiki: United States, Bureau of Land Management Tract Books Coverage Table (FamilySearch Historical Records)

Whether you are motivated to search these types of records depends entirely on how strongly you feel about finding your ancestors. For further information on these valuable records see Research in the Land Entry Files of the General Land Office (Record Group 49) and also the Research Wiki at United States, Bureau of Land Management Tract Books (FamilySearch Historical Records)