Ten years after the arrival of the first Georgia, Carolina and North Railroad passenger train, Jug Tavern was again renamed; this time as the City of Winder. Local officials approved the name change in 1893, and the change became official by an Act passed by the Georgia General Assembly on December 24, 1894. Named for the general manager of the Seaboard Railway, John H. Winder, the City's boundary was enlarged to encompass a one-mile circle extending from the same crossing of the railroad of Broad Street. Similar to Jug Tavern, the town was governed by a mayor, but now with six aldermen, who had the power to issue bonds for public schools, water works and other purposes. The last mayor of Jug Tavern and the first of Winder was H. S. Segars.
Considerable growth occurred in Winder during the 1890s. As the 20th Century arrived, banks had been established as well as offices for attorneys, doctors, dentists, undertakers, real estate operations and blacksmiths. A drugstore came into existence and, in 1900, the Winder Telephone Company opened. While farming remained the chief occupation of most of the area's citizens, many residents began working in newly forming manufacturing enterprises, including Winder Foundry and Machinery, Bell Overall, Smith Hardware and Winder Cotton Mill (later the Winder Rug Mill). Retailing also grew in Downtown: general merchandisers, drugstores, dry goods, sundries and bakeries. Four churches were constituted, a hotel was built, and a volunteer fire department was formed. Increasingly, Winder became an important trade center in eastern Georgia.
Being situated in three counties caused continuous legal problems and governance confusion for the residents and businesses of Winder. It required almost 75 years, following many aborted efforts, for Barrow County to be established. Finally, on July 7, 1914, the Georgia General Assembly carved territory from Gwinnett, Jackson and Walton counties to create the new county, with Winder as the County seat. Each of these counties utilized a river as the line which would separate the donated land in the former counties from the future Barrow County. The new county was named for the Chancellor of the University of Georgia, David Crenshaw Barrow. A handsome new courthouse, designed by James J. Baldwin, was completed in 1920 at a cost of $133,400; the building is now listed on the National Register of Historic Places. Other towns brought in with the establishment of Barrow County included Auburn, Bethlehem, Carl and Statham.
Winder continued to prosper during most of the first half of the 20th Century. Industries undertook the manufacture of overalls, hardware, textiles and the processing of cotton. Additional banks opened and, in 1907, the Winder News began publishing. After World War I, during which Winder contributed many young men, major public investments were made, including the paving of Broad Street, creation of an electric light system and construction of a waterworks. Highway 29 was paved from Lawrenceville to Winder in 1930, and, during the following year, a nearby local resident, Richard B. Russell, Jr., was inaugurated as governor of Georgia. Later, upon his election to the U.S. Senate, Russell obtained an appropriation, in 1943, to construct a local airport, which was opened in 1948.
Many important events helped to modernize Winder after World War II. Major public improvements led this modernization, inluding the Winder-Barrow County Hospital, the groundbreaking ceremony taking place in August of 1950. Construction was begun on the new Federal Building, which opened in 1967, the same year which saw Fort Yargo become a Georgia State Park. During the late 1970s, important investments were made in Downtown, including the restoration of the depot, improvements to downtown sidewalks, and renovation of City Hall and the police and fire stations. Following a fire that destroyed two buildings at Broad and Candler streets, the City created a small park and parking lot on the site. Plans were drawn for a civic center and new police and fire facilities, which were completed in 1986. A new headquarters for the Piedmont Regional Library was dedicated in 1988, and the new Barrow County Courthouse annex was opened in 1990. That year, Winder was a City of 7,373 inhabitants.
All of these accomplishments were celebrated by the citizens of Winder in 1993, with the commemoration of the City's 100th anniversary. A bronze marker was attached to the Winder City Hall by Mayor Buddy Outzs, which read: "To commemorate 100 years as the City of Winder, 1893-1993."