Tanah Merah, a residential suburb at the junction of the Logan River and Slacks Creek, is 6 km south-east of central Logan and 27 km south-east of central Brisbane. The origin of the name is uncertain, although a Malayan or Indonesian source has been suggested.
The north-east border is the Pacific Highway (now the Pacific Motorway), and the Logan Motorway skirts the suburb. Facing the Logan Hyperdome shopping centre on the Pacific Motorway, the northern part of Tanah Merah is rural/residential. When first defined as a suburb, Tanah Merah's other boundary, approximating Plumbs Road, enclosed only the rural/residential part. The more built-up part was Loganholme, and the present suburb (and postcode area) encloses what formerly was Loganholme North.
With the Hyperdome facility on Tanah Merah's northern boundary, only small local shopping centres are in the suburb. The school situation is similar, with Loganholme and Shailer Park Primaries and Shailer Park High in adjoining suburbs. Tanah Merah has several local parklands and Tansey Park on the Logan River.
The census population of Tanah Merah in 2006 was 4559.