Judge Deborra Garrett was sworn in Friday in the council chambers at the Whatcom County Courthouse.
County voters elected Garrett to the Superior Court bench in the general election last November after she got 52.6 percent of the vote over District Court Judge Dave Grant.
KGMI legal analyst Jeffery Lustick says the swearing in was an historic occasion for the courts in Whatcom County.
Lustick says the county council chambers were filled beyond capacity for Friday's swearing in ceremony.
Garrett has been a member of the Bellingham and Lynden firm of Zender Thurston since 1993.
She recently stepped down as president of the Whatcom County Bar Association.
Whatcom County was the last county in the state to have a woman elected to its superior court bench.