Spanish forces invaded the Georgia colony during the War of Jenkins' Ear. Oglethorpe took charge of the defense and led a local militia to victory in the Battle of Bloody Marsh on St. Simons Island, assuring English ownership of the colony. Oglethorpe went to England the following year and never returned. Royal governors administered the colony for the next two decades.

Georgia in 1735 prohibited slavery; it was the only one of the 13 Colonies to do so. This lasted until 1749. The following year began a very large influx of slaves; from 1750 to 1775, the slave population grew from 500 to 18,000. Planters and plantations proliferated.

Georgia residents threw in their lot with their northern neighbors to protest the Stamp Act and other taxes that they thought unfair. Georgia sent representatives to the Second Continental Congress; Georgia representatives signed the Declaration of Independence. A state constitution, adopted on Feb. 5, 1777, created the states's first counties.

During the Revolutionary War, as with as other colonies, the overall Georgia population was divided in its loyalties. Patriots made their stronghold in Augusta. British forces took over the city of Savannah and some of the surrounding area in 1778 and then seized Augusta the following year. British forces withstood a 1779 siege by a combined American-French force, and Great Britain retained a Loyalist government until the end of the war. One bright spot for the Americans was a victory at the Battle of Kettle Creek, in the northern part of the colony. Georgian forces also made three sorties into Florida, attacking British interests there. Patriots forces recaptured Augusta in 1781, and British forces left Savannah the following year.

With the war over, Americans got on with the process of making a new government. Georgia sent representatives to the Constitutional Convention and signed the Constitution. And on Jan. 2, 1788, Georgia ratified that Constitution and became the fourth state in the Union.