Sarah Foster was born on June 30, 1709, also in Billerica. Her parents were Thomas and Hepzebah (Sawtell) Foster.

David and Sarah were married before 1727 (one source says 1725), presumably in Billerica since their first three children were born there:

In 1732, the family moved slightly further inland to Shrewsbury, Massachusetts. The children continued:

• Hannah Crosby
• Solomon Crosby
• Persis Crosby
• Mary Crosby
• John Crosby
• Bulah Crosby
• Relief Crosby
• Prudence Crosby
• Rachel Crosby

David Crosby died before 1759 in Middletown, Connecticut. Sarah (Foster) Crosby died in East Hartford, Connecticut on an unknown date.