Unlike most lighthouses on this coast, Highland Light can normally be climbed, and that makes it the one to pick if you want to stand in a lantern room on Cape Cod.
The grounds are open year-round and free. The tower itself opens to the public in season — in recent years from around May until late October — with guided access, a small admission and a queue at busy hours. Days, hours and prices are set each season and are not worth guessing; check with the Truro Historical Society or the National Park Service before you drive out for it.
A minimum height rule applies to climbers, as it does at most working towers, so check before you promise a small child the top. The stair is a spiral with a final ladder section into the lantern, and the gallery is narrow.
What you get from the top is the best view on the Outer Cape: the Atlantic in a long curve north toward Provincetown and south past Wellfleet, the narrow spine of Truro, and on a clear day Cape Cod Bay on the other side. It is the view that explains the geography of the whole peninsula in about ten seconds.
The Highland House Museum next door is a separate admission and a genuinely good small local museum.