If you're in line when polls close, you are guaranteed a chance to register and vote by NH Section 659:12

Curious when and where to track the results of today's election? Results aren't expected to start till 7:00 PM EST (0000 UTC).

Note most elections are called when a confidence level has been achieved, but can take hours or days to actually be completed. You'll usually see an election being called but until the state says counting is done it's not over. A good rule of thumb is to just check tomorrow for more accurate results.

• NH Gov Elections Site
• NPR Election Reporting
• WMUR Election Reporting