Worcester County is a county in the U.S. state of Massachusetts. At the 2020 census, the population was 862,111, making it the second-most populous county in Massachusetts. It is also the largest county in Massachusetts by geographic area. The largest city and traditional shire town is Worcester, Massachusetts. Worcester County is part of the Worcester, MA-CT metropolitan statistical area and as the Boston-Worcester-Providence, MA-RI-NH-CT combined statistical area. History Worcester County was formed from the eastern portion of colonial Hampshire County, the western portion of the original Middlesex County and the extreme western portion of the original Suffolk County. When the government of Worcester County was established on April 2, 1731, Worcester was chosen as its shire town (later known as a county seat). From that date until the dissolution of the county government, it was the only county seat. Because of the size of the county, there were fifteen attempts over 140 years to split the county into two counties, but without success. Initially, Lancaster was proposed as the seat of the northern county; later, Petersham was proposed once and Fitchburg was proposed repeatedly, most recently in 1903. Perhaps as a concession, in August 1884 the Worcester County Registry of Deeds was split in two, with the Worcester Northern registry placed in Fitchburg. Geography According to the U.S. Census Bureau, the county has a total area of , of which is land and (4.3%) is water. It is the largest county in Massachusetts by area. The county is larger geographically than the entire state of Rhode Island even including Rhode Island's water ocean limit boundaries. The county constitutes Central Massachusetts, separating the Greater Springfield area from the Greater Boston area. It stretches from the northern to the southern border of the state. The geographic center of Massachusetts is in Rutland. Worcester County is one of two Massachusetts counties that borders three different neighboring states; the other being Berkshire County. They are also the only two counties to touch both the northern and southern state lines. Adjacent counties Cheshire County, New Hampshire - north Hillsborough County, New Hampshire - north/northeast Middlesex County, Massachusetts - east/northeast Norfolk County, Massachusetts - east/southeast Providence County, Rhode Island - south/southeast Windham County, Connecticut - south Tolland County, Connecticut - south/southwest Hampden County, Massachusetts - west/southwest Hampshire County, Massachusetts - west Franklin County, Massachusetts - west/northwest National protected areas Blackstone River Valley National Historical Park (part)