Just a shade under 4 stars for me, so I rounded up. 
 I had this grouped with my steampunk books- mostly because when I first found out about it, it was on lists of steampunk books. I've since changed that to fantasy. It does have an alternate late 1800s US (where magic drives expansion, the military, and more), and there is one mechanical beastie, but mostly it feels like a fantasy to me. 
 We start in a small town in the Sierras (I love this part of the US, so I was drawn to it immediately). Emily is a Witch, crafting charms for her town, taking care of her adoptive father, and working a love charm to get the richest man in town to marry her (so that she can provide for Pap). 
 A warning of trouble with zombies at the mine has her racing to help, along with Dreadnought Stanton, a warlock studying "primitive local magic". Emily ends up with a strange stone embedded in her hand, and now she must be off to San Francisco to discover what is happening, as well as to get it out so her life can return to normal. They'll encounter deadly magic, Indians, betrayals, secret societies, and magic users of every kind. 
 I really enjoyed the worldbuilding. Discovering this magical America was a lot of fun. Stanton and Emily have an antagonistic relationship throughout most of the book, but work well together. I enjoyed the other supporting characters as well, although near the end so many new faces were thrown in that it was a little confusing. 
 I will be looking for the next book from Hobson.