State Route 204 begins just east of Pembroke at US 280/SR 30 and ends in Savannah at I-16 exit 165 (37th Street).

In Savannah, this is a very major and heavily traveled surface arterial and is known as Abercorn Expressway, Abercorn Street and 37th Street. The portion of the route running along Abercorn Street was previously numbered as State Route 359.

State Route 204 begins five miles east of Pembroke at US 280/SR 30 in the Lanier community and ends in Savannah at I-16 exit 165 (37th Street Connector).

The highway is two lanes as it travels east through rural Bryan County and the Ellabell Community. Once it crosses the Ogeechee River and enters Chatham County, the highway becomes known as Fort Argyle Road. Development is more noticeable as one travels east, and there is a large collection of businesses catering to the traveler at the interchange with I-95. It is at this interchange that the highway changes from two lanes to four divided lanes. Traffic is often quite heavy as State Route 204 is the major route from I-95 into the busy south side of Savannah. Though State Route 204 is known as Abercorn Expressway as it enters Savannah, it is not a true expressway. While there are freeway-style interchanges with both US 17 and Veterans Parkway, there are at-grade signalized intersections at Grove Point Road and King George Boulevard, which can cause traffic delays, especially due to the timing at the King George Boulevard signal. The speed limit is 45 miles per hour. At the intersection with Rio Road, adjacent to the Savannah Mall, the highway becomes six lanes divided and remains as such until the intersection with DeRenne Avenue, where it becomes four lanes as it enters historic residential areas. State Route 204 continues to follow Abercorn Street north for several blocks to its intersection with 37th Street. Here it turns left and follows 37th Street, a four lane divided surface arterial, west for a number of blocks. Just west of its intersection with Bulloch Street, State Route 204 bears right to follow the short 37th Street Connector, which leads to I-16, and thus the end of State Route 204.

The portion of the route running along Abercorn Street was previously numbered as State Route 359.

Georgia State Route 204 Spur is a connecting spur to Skidway Island State Park. It also serves as the temporary southern terminus of the Harry S. Truman Parkway. Segments of the route includes East Montgomery Cross Road, Waters Avenue, Whitfield Avenue, Diamond Causeway, and Tidewatwer Way.