Anguilla (in orange) relative to Puerto Rico (shown by the flag in the image).
Anguilla is about 140 miles east of Puerto Rico (the large island under the flag in the image below). The World Atlas web site has a nice map of the Caribbean.

Long and narrow, Anguilla got its name from eels.
Because of its shape, Anguilla got its name from the scientific name for eels. The local Arawak tribes called the island Malliouhana.
Below is a simple map of Anguilla taken from Anguilla-Beaches.com. The map itself came from Google maps.

Skyviews has a much more detailed, very high quality map of Anguilla. Be warned: it takes a long time to load.