East Florida was a colony of Great Britain from 1763 to 1783 and of Spain from 1783 to 1822. East Florida was established by the British colonial government in 1763; as its name implies it consisted of the eastern part of the region of Florida, with West Florida comprising the western parts. Its capital was St. Augustine, which had been the capital of Spanish Florida.
Britain formed East and West Florida out of territory it had received from Spain and France following the French and Indian War (the Seven Years' War). Finding its new acquisitions in the southeast too large to administer as a single unit, the British divided them into two colonies separated by the Apalachicola River. East Florida comprised the bulk of what had previously been the Spanish colony of Florida. Britain ceded both Floridas back to Spain following the American Revolutionary War, and Spain maintained them as separate colonies, though the majority of West Florida was gradually annexed by the United States. Spain ceded East Florida and the remainder of West Florida to the US in the Adams-Onís Treaty; the United States organised them as a single unit, the Florida Territory.
British period 
Under the terms of the Treaty of Paris, which ended the Seven Years' War (the French and Indian War), Spain ceded Spanish Florida to Britain. At the same time, Britain received all of French Louisiana east of the Mississippi River, with the exception of New Orleans, from France. Determining the new territory too large to administer as one unit, Britain divided its new southeastern acquisitions into two new colonies separated by the Apalachicola River: East Florida, with its capital in the old Spanish city of St. Augustine, and West Florida, with its capital at Pensacola.
The settlement of East Florida was heavily linked in London with the same interests that controlled Nova Scotia. The East Florida Society of London and the Nova Scotia Society of London had many overlapping members, and Council frequently followed their suggestions on the granting of lands to powerful merchant interests in London.
Perhaps it is strange to think of such dissimilar geographic areas with such opposing climates as having much in common," said the Florida Historical Quarterly. "But if one considers naval and military strategy, one can see that these areas have a common significance, especially when viewed from London by the ministry. Halifax (Nova Scotia) was the command post for both the admiral and general in charge of the American forces.... St. Augustine evoked the same strategic considerations. These posts have been described as the two centers of strength to which the British army was withdrawn in the late 1760s."
The apportionment of lands in the new colonies fell to the same group of English and Scottish entrepreneurs and merchant interests, led chiefly by the Englishman Richard Oswald, later a diplomat, and the British General James Grant, who would later become governor of East Florida. A list of the grantees in both Florida and Canada show that the plums fell to a well-connected—and inter-connected—group. Lincoln's Inn barrister Levett Blackborne, grandson of Sir Richard Levett, a powerful merchant and Lord Mayor of London, came in for grants of 20,000 acres (81 km2) in both locales, for instance. Other aristocrats, nobles and merchants did the same.
The influx of loyalists following the outbreak of civil war in the northern colonies had a pivotal effect on every aspect in East Florida society. The loyalists’ population transformed the formerly backward colony into a model colony able to cope with the ever increasing population and the associated demands than came along with it. The colony was previously governed without a legislative council but with the influx of the loyalists, demand for an elected representative body grew and in 1775 an unelected Grand Jury was formed. In correspondence with Lord Germain, Governor Tonyn stated the loyalist's desire for an elected governing body. In March 1781 Governor Tonyn called elections for the creation of a representative provincial Assembly. Of the 19 elected only four had arrived prior to the revolution, the rest were loyalists.
The most powerful lubricant between the East Florida speculators and the Nova Scotia speculators was Col. Thomas Thoroton of Flintham, Nottinghamshire. Thoroton, the stepbrother of Levett Blackborne, had married an illegitimate daughter of the Duke of Rutland and often lived at Belvoir Castle, where he acted as principal agent to the Duke, who, along with his son the Marquis of Granby, were heavily involved in overseas ventures. Thoroton frequently acted as the go-between for Richard Oswald and James Grant, particularly after those two gave up their Nova Scotia Grants to focus on East Florida, where a drumbeat of steady speculation (particularly from Dr. Andrew Turnbull and Dr. William Stork) had fanned the flames of interest in London.
Both Floridas remained loyal to Great Britain during the American War of Independence. Spain participated indirectly in the war as an ally of France and captured Pensacola from the British in 1781. In the Treaty of Paris, which ended the war, the British ceded both Floridas to Spain. The same treaty recognised the independence of the United States, directly to the north.
Spanish period 
Spain continued to administer East and West Florida as separate colonies. The Spanish offered favourable terms for acquiring land, which attracted many settlers from the newly formed United States. There were several territorial disputes between the US and Spain, some resulting in military action. An American army under Andrew Jackson invaded East Florida during the First Seminole War. Jackson's forces captured St. Mark's on 7 April 1818 and Pensacola on 24 May 1818. James Monroe's Secretary of State John Quincy Adams defined the American position on this issue. Adams accused Spain of breaking Pinckney's Treaty by failing to control the Seminoles. Faced with the prospect of losing control, Spain formally ceded all of its Florida territory to the US under the Adams-Onís Treaty in 1819 (ratified in 1821) in exchange for the US ceding its claims on Texas and the US paying any claims its citizens might have against Spain up to $5,000,000.
In 1822, the US Congress organised the Florida Territory. In 1845, Florida was admitted as the 27th state of the United States.
See also