In 1830, Roswell King passed through the area that would become Roswell and noted the potential for building a cotton mill along Vickery Creek. In 1836, he returned to build the largest mill in north Georgia--Roswell Mill. King invited investors from the coast to join him at the new location, including his son Barrington King, and Roswell officially became a city on February 16, 1854.

When Martha "Mittie" Bulloch was four, her family moved to Roswell. Her father, who had partnered with Roswell King to build the new cotton mill, built a mansion called Bulloch Hall, which is listed on the National Register of Historic Places as a significant antebellum structure. On December 22, 1853, Mittie married Theodore Roosevelt Sr. in Bulloch Hall. Five years later, she would give birth to Theodore Roosevelt Jr.--the 26th President of the United States.

The southern boundary of the city follows the Chattahoochee River.

Dr. Francis Goulding, an early Roswell resident and author of children's books, invented the modern sewing machine for his wife in 1841--three years before English inventor John Fisher invented a similar machine. Unfortunately, Goulding doesn't get any credit for the invention because he failed to obtain a patent.

On July 5, 1864, the city was captured by Union forces under the leadership of General Kenner Garrard. Under orders of General Sherman, Garrard burned the mill and shipped the mill workers north to prevent them from returning to work if the mills were rebuilt. The ruins of the mill and the 30-foot (9.1 m) dam that was built for power still remain.

Telephone service came to Roswell in 1901. All phone numbers were one digit.

Peter Buck, co-founder and the lead guitarist of the alternative rock band R.E.M., lived in Roswell and graduated from Crestwood High School in 1975.

Roswell's first traffic signal was installed in 1949 at the intersection of Sloan and Atlanta streets.

Public House, known as Peasant Restaurant in the 1970s, is one of Roswell's most significant historical sites. It was originally a commissary for the Roswell Mill constructed in 1854. The building housed the Dunwoody Shoe Shop in 1920 and had a funeral home upstairs. It was a Union hospital during the Civil War, and as legend goes, is the site of tragedy surrounding a forbidden romance between Michael, a Union soldier, and Catherine, a Southern Belle nurse. When Michael was killed by Confederate soldiers, some say Catherine hanged herself nearby, but according to some locals, their spirits linger here, dancing in the loft, playing piano, or playing tricks on employees by moving glasses across the bar.

George Napoleon "Nap" Rucker was a left-handed pitcher in Major League Baseball for the Brooklyn Superbas/Dodgers/Robins. Over his 10 seasons, Rucker lead the league in Shutouts, Complete Game, and Innings Pitched, and on September 5, 1908, he became the first left-handed pitcher to throw a no-hitter in Dodger history. He served as mayor of Roswell from 1935 to 1936 and was responsible for creating Roswell's first supply of running water.