Myra was a planet located in or near Federation space in the galaxy's Alpha or Beta Quadrants. It was the homeworld of developing Myra natives.
History and specifics
Myra was a lush paradise with semi-tropical conditions. Its surface featured a large number of islands and oceans.
In the 2270s, Pavel Chekov and Friedman enjoyed their visit to Myra. When they later beamed down to harsh Kappa Rho IV, Friedman lamented that not every planet could be Myra. (TOS - Star Trek II Short Stories short story: "Intelligence Test")