The Lebuh Acheh Mosque (Acheen Street Mosque) was built in 1808 by the Acehnese tunku (prince) Syed Hussain Aidid, who settled in Penang at the start of the British period and led a small community of Sumatran Muslim merchants. The mosque is the oldest in central Georgetown and one of the most architecturally distinctive: the minaret is a square Egyptian-style tower with a domed top, a form rare in Southeast Asia, while the prayer hall has carved teak doors and a sober green-and-white colour scheme.
The surrounding quarter was once a thriving Malay Muslim merchant district, the centre of the haj trade — pilgrims from the Dutch East Indies stopping in Penang on their way to and from Mecca. The mosque was the hub of religious life and Islamic scholarship. The building was restored by the state heritage authority in the 2000s. Open to non-Muslim visitors outside prayer times; modest dress and bare feet expected. Worth a short visit on the walk between the Khoo Kongsi and the Pinang Peranakan Mansion.