Trehörnings masugn stands at Mariedamm, east of Askersund, as a reminder of the area's iron industry. The venue says the Lerbäck mining district was established in the 1320s, when the first mines and furnaces were built. The first furnace at Mariedamm began operating in 1636 and was shut down in 1889. It was rebuilt as a mulltimmerhytta, a timber-framed blast furnace, in 1781. The present furnace was renovated and reopened in 1995; the venue describes it as Sweden's best-preserved example of this type.

You can book a guided tour of the furnace in advance. The tour takes about 30 to 45 minutes. A summer-open coffee hut is on the grounds. The nearby former English park also offers guided tours by arrangement.

Mariedamsleden, a walking trail, starts at the furnace. Its gently hilly route has a 4-kilometre and a 9-kilometre option. Sights along the trail include Solberga meadow, Runsala ravine and the Torrgruvorna mines. By Lake Trehörningen, there is a rest area with a wind shelter and a fire pit.

The site is not adapted for people with reduced mobility, but it has an accessible visitor toilet. The website gives no prices. The coffee hut is open in summer; guided tours are booked in advance.