In 1848 30-year-old Mason walked 1,700 miles behind a 300-wagon caravan that eventually arrived in the Holladay-Cottonwood area of the Salt Lake Valley. On the way west Mason’s responsibilities included setting up and breaking camp, cooking the meals, herding the cattle, and serving as a midwife. Along with taking care of her three young daughters aged ten, four, and an infant.

In 1851 Smith and his family and slaves set out in a 150-wagon caravan to San Bernardino, California to establish another Mormon community. Ignoring Brigham Young’s warning that slavery was illegal in California, Smith brought Mason and other enslaved people to California.  Along the way Mason met Charles H. and Elizabeth Flake Rowan, free black people, who urged her to legally contest her slave status once she reached California, a free state.  Mason also got an additional push by free black friends whom she met in California, Robert and Minnie Owens.

In December 1855 Robert Smith, was fearful of losing his slaves, decided to move with them to Texas, a slave state. The Owens family who had a vested interest in the Mason family as one of their sons was romantically involved with Mason’s 17-year-old daughter.  When Robert Owens told the Los Angeles County Sheriff that slaves were being illegally held, he gathered a posse which including Owens and his sons, other cowboys and vaqueros from the Owens ranch.  The posse apprehended Smith’s wagon train in Cajon Pass, California on the way to Texas and prevented them from leaving the state.

After spending five years enslaved in a “free” state Bridget Mason challenged Robert Smith for her freedom.  On January 19, 1856 she petitioned the court for freedom for herself and her extended family of 13 women and children. Los Angeles District Judge Benjamin Hayes took three days before handing down his ruling in favor Mason and her family, citing California’s 1850 constitution which prohibited slavery.

Mason and her family moved to Los Angeles where her daughter married the son of Robert and Minnie Owens.  Mason worked as midwife and nurse, saved her money which helped her purchase land in the heart of what is now downtown Los Angeles. She accumulated a fortune worth about $7.5 million in today’s dollars, making her one of the richest women in Los Angeles. Mason organized First A.M.E. Church, the oldest African American church in the city.  She educated her children and with her wealth became a philanthropist to the entire Los Angeles community.  Bridget “Biddy” Mason died in Los Angeles in 1891.