Wikia

Lake Armstrong was a location on Earth's moon.

By 2373, it was large enough to be seen from Earth during the day, since Commander William T. Riker enjoyed looking at the unfamiliar sight of its absence while looking at the Moon during his mission to the year 2063. (Star Trek: First Contact)

Lake Armstrong was named after Neil Armstrong, who was the first Human on Earth's moon in 1969. (Star Trek Encyclopedia 2nd ed., p. 22)