The city of Dale was founded in T.A. 2590. It was settled near the mountain of Erebor, which was settled by the Dwarves in the same year. The city was destroyed by the Dragon Smaug in 2770. 

History

? - T.A. 2590: Before the Founding

Before the founding of the city, the Dale itself was occupied by dozens of small villages and hamlets, organized around small clans ruled by elected chiefs. Ancient traditions and laws, passed down both through tale and through the carved runestones that dotted the landscape, governed life in the area. These included the Rites of the Free People, though there were many variations in law and tradition. 

In T.A. 2489, the Easterlings drove many of the Northmen south of the Dale north, wreaking havoc and causing great destruction in the area. Many small settlements were burnt, and hundreds enslaved. 

T.A. 2590: Founding of Erebor & Dale

Driven from the north, the dwarves led by Thror march to the Lonely Mountain, and found the city of Erebor. In payment to the men who inhabit the Dale for the rites of settlement, the dwarves provide the men of the region with arms and armor of dwarvish make, allowing them to drive back the Easterling threat. The first true Lord of Dale, Riddard, leads an army against the Easterlings and drives them back. On his return, he founds the city of Dale and the people of that region are united. 

T.A. 2590 - 2720: Time of Plenty

As Erebor prospered, so did Dale. Even Esgaroth down on Long Lake grew, and the Free People of the North were proud. The Lordship of Dale passed in 2635 to Riddard's son, Brynn, who served as a just and humble ruler of the Dale. Brynn served from 2635 to 2665, when he was felled by the poisoned arrow of an Easterling assassin. Being without heir, his brother Cerion took the Lordship in 2665, and served long until 2720 when he passed quietly on his throne. And so Girion, son of Cerion, Lord of the Dale, came to rule in the spring of T.A. 2720. 

T.A. 2720 - 2758: Lordship of Girion

T.A. 2758 - 2759: The Long Winter

T.A. 2770: The Fall of Dale