Atlantic Patagonia's Central City
Trelew is sort of the central hub for the Atlantic coast section of Chubut. It was founded in 1886 when the railroad to the coast was built. You will land here if you fly in from Buenos Aires. There isn't too much here to interest the average tourist, but starting from here you can easily access Gaiman, Punto Tombo, Puerto Madryn, and further afield, Peninsula Valdes.
There is a Visitor's Center on Mitre near the Plaza and the central part of the city is set out in a grid pattern so it's not too difficult to drive around, although most of the streets are one way and that can be inconvenient.

Statue of the Welsh Settlers
A small section of the Penguin nesting area
Ruth and a giant femur
Interior of Hotel Touring Club