Are three airports or four required for private pilot cross country? The cross country requirement for the private pilot certificate says that I need to complete a cross country flight of over 150 nm with full stop landings at three points and one leg at least 50 nm.  Does that mean three full stop landing points other than the primary airport, or three including the primary airport?  So if I take off from Airport A, fullstop land at Airport B, fullstop land at Airport C, then return to Airport A, is that good enough?  Or do I also need to visit Airport D for a total of three fullstop landings away from my primary airport?
The regulation means you need to land at three separate airports.  This should include landing at your original departure airport at the end of the flight.

§61.109(a)(5)(ii)
One solo cross country flight of 150 nautical miles total distance, with full-stop landings at three points, and one segment of the flight consisting of a straight-line distance of more than 50 nautical miles between the takeoff and landing locations