Absolute frequency measurement of the 7s$^2$ $^1$S$_0$ $-$ 7s7p $^{1}$P$_1$ transition in $^{225}$Ra

Transition frequencies were determined for transitions in Ra in an atomic beam and for reference lines in Te$_2$ molecules in a vapor cell. The absolute frequencies were calibrated against a GPS stabilized Rb-clock by means of an optical frequency comb. The 7s$^2,^1$S$_0$(F = 1/2)-7s7p$,^1$P$_1$(F = 3/2) transition in $^{225}$Ra was determined to be $621,042,124(2),$MHz. The measurements provide input for designing efficient and robust laser cooling of Ra atoms in preparation of a search for a permanent electric dipole moment in Ra isotopes.