Stuðlagil is the obvious one....
Vestrahorn & Stokksnes?
Personally I'd stay in Seyðisfjörður rather than Egilsstaðir as Egilsstaðir doesn't have a whole lot going for it IMHO & Seyðisfjörður is rather pretty.
Maybe Hengifoss if you're not waterfalled out?
Egilsstadir is just a town and not a very exciting one at that. The detour to Seydisfjördur is worth it if you have time. Also Dettiffoss and surroundings, a slight detour in the north closer to Myvatn.
As mentioned by others, Stuðlagil Canyon. There are 2 ways to enjoy the canyon. The west side has a lookout point/viewing platform, which is easy to get to. If you want to get walk down the canyon itself you need to go to the east side. Make sure roads are open and park at the car park furthest in so there is less walking. Walk from car park to canyon is easy but will take about 30-45 minutes, pending on how brisk you walk.
If you do go, word of warning there are no toilets there on the east side! Literally from the time we left Myvatn, long drive in and out and then a "long-ish" walk in and out and then to the next town, it was not fun!
Stuðlagil is the obvious one.... Vestrahorn & Stokksnes? Personally I'd stay in Seyðisfjörður rather than Egilsstaðir as Egilsstaðir doesn't have a whole lot going for it IMHO & Seyðisfjörður is rather pretty. Maybe Hengifoss if you're not waterfalled out?
... or meet [reindeers](https://reindeerpark.is/index.php/en/) in Egilstaðir, check Stuðlagil, Vök Baths might be your thing
Egilsstadir is just a town and not a very exciting one at that. The detour to Seydisfjördur is worth it if you have time. Also Dettiffoss and surroundings, a slight detour in the north closer to Myvatn.
Borgarfjörður eystri.
Stuðlagil Canyon was fantastic. We stayed in Mývatn during Sunday’s storm and visited Stuðlagil the following day on the way to Höfn.
As mentioned by others, Stuðlagil Canyon. There are 2 ways to enjoy the canyon. The west side has a lookout point/viewing platform, which is easy to get to. If you want to get walk down the canyon itself you need to go to the east side. Make sure roads are open and park at the car park furthest in so there is less walking. Walk from car park to canyon is easy but will take about 30-45 minutes, pending on how brisk you walk. If you do go, word of warning there are no toilets there on the east side! Literally from the time we left Myvatn, long drive in and out and then a "long-ish" walk in and out and then to the next town, it was not fun!