Chelsea Clock Company
Founded in 1897 in a Massachusetts factory that had already outlived several clock companies, Chelsea became known for ship's bell clocks and still makes clocks today.
A factory with several lives
Chelsea Clock was not the first clockmaker in its building. The company's own timeline says its early names changed from Harvard to Boston to Eastman before it settled on Chelsea Clock Company in 1897.
The Chelsea Clock Museum website, a collector-run site, fills in the sequence. It describes the original Boston Clock Company of 1884 to 1894, Joseph H. Eastman's Eastman Clock Company of 1894 to 1896, and a short-lived Boston Clock Company of Maine set up by Harry Bates in Eastman's former factory. In mid-1897, the site says, Charles H. Pearson founded the Chelsea Clock Company and took over that factory and its materials.
Timekeeper of the sea
The company says it signed its first contracts with the U.S. Navy, the U.S. Army and Tiffany and Co. in 1899, and that it designed and patented its first ship's bell mechanism in 1900. In 1911 Walter Menns patented the Chelsea automatic ship's bell clock.
Military orders shaped the business. Task and Purpose reports that Chelsea became the first supplier of timepieces for Navy ships when the government began ordering marine clocks, building them with forged brass cases sealed with lacquer to resist salt water and rough handling. In 1910 the company created a separate brand, Boston Clock, for clocks made to government standards.
World War II was its busiest period. Chelsea says it produced more clocks in four wartime years than in its whole history since 1897, with women filling many factory jobs, and it received the Army-Navy E Award for production in 1943.
See also: the main families of clocks, from marine to mantel on OnlineClock.app.
Cars, planes and presidents
Chelsea did not only make clocks for ships. The company says it began making dashboard clocks for Rolls-Royce in 1903 and later for Ford, adapted its car clock for airplanes in 1917, and added electric clocks in 1930. In 1936 Admiral Byrd thanked the firm for clocks used on a South Pole expedition.
Its clocks also became official gifts. Task and Purpose reported in 2017 that every U.S. president since Theodore Roosevelt had owned or displayed a Chelsea clock, and that President Obama gave engraved Chelsea Dartmouth clocks to diplomats. The company's timeline dates Obama's choice of the Dartmouth to 2009.
Dating a Chelsea clock
Chelsea movements carry serial numbers, and collectors use them alongside surviving factory records. The Chelsea Clock Museum site cites the factory record book for examples: clock number 204, sold on September 13, 1897, was only the second clock Chelsea sold, and the oldest known Chelsea clock of the Yacht Wheel design, recorded as number 15273, was sold through the New York retailer Theodore B. Starr in 1905.
Watch the name on the movement. That clock number 204 is marked Boston Clock Co., because Chelsea's first sales included marine and regulator clocks made by its predecessor. Boston Clock was also the name of the government-standard brand Chelsea created in 1910, so a Boston Clock mark alone does not settle the date.
Printed catalogs help too. The collector site notes that Chelsea catalogs were identified by letter until 1928 and numbered from catalog 14 afterward, while the company says its earliest known catalog dates from 1906.
Chelsea today
Chelsea marked its centennial in 1997 with a Centennial Clock and limited editions honoring the USS Constitution, and in 2015 it moved into a new factory building a few blocks from the original. As of 2026 the company's website says it still manufactures and repairs clocks at its headquarters in Chelsea, Massachusetts, and in 2017 Task and Purpose described its repair shop as the country's largest branded clock repair facility.
See also: what to expect when a clock goes in for service on OnlineClock.app.
Questions people ask
How can I find out when my Chelsea clock was made?
Note the serial number on the movement and the name stamped there. Collectors match serial numbers against Chelsea's factory records and catalogs; a Boston Clock Co. mark can mean an 1897 transitional clock or the later government-standard brand.
Is Chelsea Clock still in business?
Yes, as of 2026. The company's website says it still manufactures and repairs clocks at its headquarters in Chelsea, Massachusetts, where it moved into a new factory building in 2015.
Has the White House used Chelsea clocks?
Task and Purpose reported in 2017 that every U.S. president since Theodore Roosevelt had owned or displayed a Chelsea clock, and the company says a custom White House clock featured in White House History Quarterly in 2021.