Peskite was originally part of the Peddleian Empire, but during it's collapse, Peskite gained it's independence.
Peskite was originally founded as the royal colony of Laureleth named after Queen Laureleth of Peddellia. Laureleth was originally supposed to reach from South Garland to the Aperture Kingdom. The Royal Colony was established in 1607 by Captain James Jay. The Laureleth Colony now exists as a state in modern Peskite. Laureleth did not reach from south Garland to Aperture, but instead reached from Garland to Erie.
Later on, it was separated into 5 colonies. These colonies were Rolumbia, Garland, Dollopova, Cumberoone, and Ashanooga. Dollopova was granted colonial state in 1654, Rolumbia in 1663, Garland in 1700, Cumberoone in 1692, and Ashanooga in 1696. The other colonies founded were Westylpenn, Albanimond, Harforcott, Providence and Montipeid. These colonies were founded between 1654 and 1700. The Eastern Shore was later acquired in 1701, and added to the Albanimond Colony. Peddellia wasn't the first empire to start colonizing the continet though, since they only started colonizing after Fayeris and Pordudrid. Pordudrid colonized the shores of modern day Tallandoglade, Raefferion, Saltillona, and Audallamo. Fayeris colonized most of modern day Loufayette, Quenanas, and Guyanette.
The various colonies everywhere would lead to many border fights and territory claims on other land. This influenced Pedellia's colonial expansion somewhat. The first major border fight happened in South Rolumbia during 1693. Peddellia tried to take land from North Tallandoglade, and the Pordudrid Empire retalliated by sending their troops up to Laureleth's former capital, Willoanoke and burning it. Willoanoke was completely burned down and the capital was moved to Chesakemps. The colonies declared a war, known as the Pordudrid-Pedellia War. The Pedellian troops went and attacked Tallandoglade's Capital, Everalasse. The Pedellian Colonies eventually won the war seven years later in 1700. They gained territory to north of Celestiona Beach, and some of that land was given to Rolumbia and the rest was founded as the colony of Garland.
The 1st Aperture Kingdom was one of the empires that gained independence. Aperture and Peskite were allies, until King Gilbert Marquis de Aperture XIV took power, and declared the Aperturian-Peskitian wars.
Although it could be considered non-canon, in the episode Revelation, Flakerot has an Earthquake after the Lamb opens the sixth seal. Shortly after, buildings are knocked over and colossal fires spread as stars fall from the sky, all the mountains there falls down, and the area itself sinks into the sea, including President Skittleflake's statue.