Jefferson County is named for Thomas Jefferson, who was President of the United States from 1801 to 1809.
Surrounding County Courthouses:
N – Powell County and Lewis and Clark County
S – Gallatin County and Madison County
W – Silver Bow County and Deer Lodge County
Created: February 2, 1865 
County Seat:
Radersburg 1865 – 1883
Boulder 1883 – present
County Courthouse – Boulder
Location: 201 Centennial Avenue / Monroe Street
Built: 1888 – 1889
Style: Richardsonian Romanesque
Architect: John Paulsen of Paulsen & McConnel of Helena
Contractor: J S McKenzie and McGowan of Boulder
Description: The building faces south and is a two story buff red colored brick and stone structure. The building is located on landscaped grounds in the center of Boulder. On the south side, the building features a projecting tall square tower capped by a steep octagonal roof and having an arched entrance on the first story. On the north side is a projecting center tower with arched entrance on the first story and twin conical towers. The building also has the semi-circular arches, rough-cut stone accents, and asymmetrical roofline. Gargoyles at the building’s corners, are perched just below the eave line. The hipped roof has dormers. The building is constructed from locally quarried granite and bricks burned within a mile of the construction site. The interior features elaborate woodwork, including decorative door and window trim and an ornately carved staircase. On the north side, a wood staircase ascends to the second story. On the second story the County District Court courtroom occupies the west side with walls rising twenty feet to a ceiling of stained beams and planking. The building houses the County District Court of the 5th Judicial District. On the west side of the building is the one story County Courthouse Annex and on the northwest side is the one story County Clerk & Recorder Office.
See: National Register of Historic Places – Jefferson County Courthouse
County Criminal Justice Center – Boulder
Location: 108 South Washington Street / West 3rd Avenue
Built: Unknown
Style: Modern
Architect: Unknown
Contractor: Unknown
Description: The building faces northwest and is a one story buff red colored brick and concrete structure. The building is located on landscaped grounds in the center of Boulder to the south of the courthouse. The northwest front has a large concrete portico with recessed entrance. The base of the building has stone facing and a narrows concrete band following the flat roof line. The building houses the County Justice Court.
See: The 5th Judicial District includes Beaverhead County, Jefferson County and Madison County.
History: The county was created in 1865 and Radersburg was selected as the county seat. The first courthouse was a two story frame structure built in 1865. The county seat was moved to Boulder in 1883. The court was housed in a building until the second and present courthouse was constructed in 1888 to 1889 at a cost of $50,000.
County Courthouse – Boulder
County District Court courtoom
County Courthouse Annex – Boulder
County Clerk & Recorder Building – Boulder
Photos taken 2011 and 2022