Question

what is the most northern latitude that can receive direct sunlight (i.e., the sun can be directly overhead at some point during the year)? answer

Answer 1

The sun can be directly overhead only at points on the Earth's surface in the "belt" around the equator between the latitudes of the two "Tropic" lines. This region on Earth is called "The Tropics".

Its southern boundary is the "Tropic of Capricorn", at roughly 23.5⁰ south latitude.

Its northern boundary is the "Tropic of Cancer" at roughly 23.5⁰ north latitude.