We consider close-packed dimers, or perfect matchings, on twodimensional regular lattices. We review known results and derive new expressions for the free energy, entropy, and the molecular freedom of dimers for a number of lattices including the simple-quartic (44), honeycomb (63), triangular (36), kagomé (3 · 6 · 3 · 6), 3-12 (3 · 122) and its dual [3 · 122], and 4-8 (4 · 82) and its dual Uni...