Orion and Walburga were married (further details are not known).
They had two sons named Sirius and Regulus.
Sirius Black
Sirius was born on August 7th, 1959. He died at the age of 36 in June 1996.
Regulus Arcturus Black
Regulus was born in 1961. He died due to murder / assassination, Murdered by Voldemort or on Voldemort's orders when he wanted out of the Death Eaters, at the age of 18 in 1979.