Old salt factory at Khlong Ong Ang mouth that continues operations to this day

Jib Hua Heng Salt Factory is an old salt factory that still remains at Phirom community, near Khlong Ong Ang mouth. In the past, salt boats from Samut Sakhon would transport grain salt for delivery, to undergo washing and grinding process before packaging into bags. Currently this factory no longer does salt grinding, but there is still a grinding mill at Maha Chai that sends salt to be stored here for sale. In the past, along the Chao Phraya River there were salt factories operating on both the Wat Chakrawat area side and the opposite side at Tha Dindaeng and Khlong San areas.

The Post Office Building, originally spelled Praisaniyakan, is the original building of the Post and Telegraph Department and Thailand's first post office. Located by the Chao Phraya River, mouth of Khlong Ong Ang, Bangkok side, south of Buddha Bridge.
The Post Office Building was demolished in 1982 to make way for construction of Phra Pokklao Bridge, which is a bridge parallel south of Buddha Bridge. Currently rebuilt in original style in a location near the original site to use as the Thai Postal Museum.