Clockwork Century Universe

Boneshaker opens Cherie Priest's Clockwork Century, a steampunk alternate history that reimagines Seattle after a mining disaster releases a toxic gas that turns people into the walking dead, forcing survivors behind a massive wall around the poisoned city. The series expands out from that starting point across the American Civil War era, following different characters and cities in each book (Clementine, Dreadnought, Ganymede, The Inexplicables, Fiddlehead, Jacaranda) rather than one continuous plot. Boneshaker was nominated for the Nebula Award and won the 2010 Locus Award for Best Science Fiction Novel.