1. Arrested as a suspect in a crime and/or convicted.

2. For certain jobs, especially ones that require extensive criminal background checks (such as mine).

3. When getting a driver's license (may vary by state).

4. When adopting children (may vary by jurisdiction).

There may be more reasons I don't know of. I've never been arrested, but I have been fingerprinted for the others. When I got my California driver's license at 17, they took a thumbprint. When I got my one for Kansas, they didn't take a print. I work for an alarm company, and several states require fingerprints on file with them or I can't work on accounts in that state. I was fingerprinted by the county of Los Angeles while briefly living with my parents when they adopted a child.

All these fingerprints are kept by and within the respective jurisdictions. They don't generally share the fingerprints without a serious reason, such as a criminal investigation.

Although I've been fingerprinted several times, if my fingerprints were found in, say, Idaho, the authorities there would have no record of them, nor would they find them in any national database. The only way they would get my fingerprints is if they had good reason to suspect I was at the scene at a specific time. If they could then figure out where I reside or work, they could then make a formal request to have any records sent to them.