One of the 'home counties' of England, north-east of London. Popularly held to be entirely populted with 'Essex girls' and the working classes but also has nice countryside and unpleasant rich people.
Nice coastline too.

I am tempted to node a completely different Essex in a completely different part of the world, but (sigh) I must finish what I started.

The domain of the "East Saxons", Essex was a separate kingdom, part of the Anglo-Saxon Heptarchy. Essex never rose to prominence like Wessex or Mercia.

Anglo-saxon kings of Essex

Aescwine (527-587)
Sledda (587-604)
Saebehrt (604-616)
Saexred and Saeward (616-617)
Sigebehrt I (617-653)
Sigebehrt II (653-660)
Swithelm (660-665)
Sighere and Sebbi (665-683)
Sebbi (683-695)
Sigeheard and Swaefred (695-709)
Offa (of Mercia) (709)
Saelred (709-746)
Swithred (746-758)
Sigeric (758-798)
Sigered (798-825)

Egbert of Wessex annexed Essex in 825. It became part of the inheritance of supernumerary sons on two occasions. The rulers of Essex after 825 are detailed in the writeups for Kent and Wessex, and later with the Rulers of England. After Alfred the Great rescued Wessex from oblivion, Essex was part of the Danelaw while that entity existed.

A class of aircraft carrier commonly used during World War II.

The Essex-Class Carrier was designed to carry two squadrons of airplanes. An Essex-Class carrier was equiped with Mark 12 radar, which allowed it to keep track of ships and enabled a multi-carrier force to maintain a high-speed formation at night or in foul weather. It was powered by eight Babcock and Wilcox boilers producing 150,000 horsepower at 32.7 knots. Known as the fast carriers, the Essex Class had a range of 15,000 nautical miles at an economical speed of 15 knots per hour.