About 5km northeast of the town is the 112m dormant volcano Kasa-yama. The pond at the mountain's base, Myōjin-ike (明神池), is connected to the sea and shelters a variety of saltwater fish. When in this area, listen and look out for the birdlife in the surrounding trees.
About five minutes' walk up the mountain from the pond is Hagi Glass , where quartz basalt from the volcano is used to make extremely tough Hagi glassware. There is a showroom and a shop with some beautiful coloured-glass vases and cups, and you can watch the glass-blowing in process. Next door is Hagi's own beer and citrus-juice factory, Yuzuya Honten . Stop in here to see the very small team at work, taste juice in the attached shop, or have a refreshing mikan-flavoured soft cream.
The road continues to the top of Kasa-yama, from where there are gorgeous views and a tiny 30m-deep crater. There is also a walking track around the coast. From late February to late March a beautiful grove of camellias here is in bloom.
Buses go to Kasa-yama from Higashi-Hagi Station once every hour to 1½ hours (¥270, 15 minutes); get off at the Koshi-ga-hama stop, about eight minutes' walk from the base of the mountain and Myōjin-ike.