Sakhon Buri was a city with continuous migration of people from other regions because the city was located at the river mouth with canals connected with the capital city. It was an important harbor town. When Siam was in contact to Western superpowers, the city was the main route carrying farm produce through Phasicharoen and Damnoen Saduak canals. Farmlands were expanding with the relocation of people under the supervision of Siam. They were granted the right to land ownership. New communities and commercial zones sprang up in Ban Phaew and Krathumbaen districts. Economic growth in the past decades demanded more labor. Migration to the province started again. This study examined the settlement history of indigenous ethnic groups and transnational ethnic migrants in the modern economic age. In terms of perspective change and interrelationship, it was found that the most prominent indigenous groups in Ban Phaew district were the Mon and Black Tai, who changed their lifestyles from paddy cultivation to vegetable and fruit plantation. They still maintained rituals relating to life and community. For the transnational migration of Mon workers from Myanmar, it was found that they usually worked in farming areas with Mon-Thai communities because they were able to communicate in their native language. In Krathumbaen district, there were laborers from various groups, such as, transnational ethnic migrant workers from Myanmar and the Plang from the highland. They were obliged to adapt to Thai society and create interrelationships with an economic dimension. Their networks were informal and separated because of fewer numbers and less support from external organizatons.