The Iron Druid Chronicles has been one of my reading "accidents." I listened to "Hammered" first because of a special promotion through Audible. I enjoyed that book and decided to try a print version of another title from the series. I expect I will be reading all eight in the series.
The main character, Atticus O'Sullivan, is as suggested a Druid. In fact, he is the last Druid. He does have an apprentice in the works and we're all pulling for Granuaile to succeed in her apprenticeship program. However, given the trouble that Atticus seems to attract, that is not guaranteed!
Atticus has a great group of friends--vampires, werewolves, and a wonderful Irish Wolfhound with whom he can "talk" telecommunicatively.
Hearne is from Arizona and the geographic connections are fascinating. He, like Neil Gaiman, Rick Riordan, and Michael Scott; brings a wide range of gods and mythological figures into his books. I'm enjoying learning a lot about Irish gods and mythology as well as other traditions. I think I'm going to have to dust off a book about druids that I got long ago and didn't finish. Now I have a reason to want to dig in more deeply. Hearne also connects to the Gaelic, Polish and German languages.
I like the entire series a lot and would recommend them to "mature" young adults. There is occasional reference to sex, but nothing particularly graphic. I think this series would be a good one for readers who like series like The Seven Realms, Chima or Codex Alera, Butcher.
In addition to enjoying the series I also believe in supporting Hearne. Before he was able to turn to writing full-time he was a high school English teacher.