The four corners of mainland US lighthousing:
NorthEast: West Quoddy
SouthEast: Key West
SouthWest: Point Loma
Northwest: Cape Flattery (aka Tatoosh Island)

Tallest: Cape Hatteras
Shortest: Probably the remains of the Cedar Point MD Light, which was the lantern room on display at NAS Pax River.
Oldest: Sandy Hook
Longest?: Navasink
Most Towers at one location: Three Sisters