St. Thomas Fort, also known as Tangasseri Fort, is located in Tangasseri, a coastal area of Kollam city in the state of Kerala, India. The fort has historical significance as it was initially built by the Portuguese in the 16th century and later came under the control of the Dutch and British colonial powers.

The fort was constructed to protect the Portuguese interests in the region and served as a trading post. Over time, it changed hands between different colonial powers, each making modifications and improvements to the structure. The British took control of the fort in the late 18th century.

St. Thomas Fort also has a connection to the apostle St. Thomas, who is said to have traveled to India and preached Christianity in the region. There is a church dedicated to St. Thomas near the fort, which adds to its historical and religious significance.

Today, the fort stands as a historical monument, attracting tourists interested in its colonial architecture and historical context. It offers a glimpse into the colonial history of Kerala and the maritime trade routes of the past.

As always, for the most current and accurate information about visiting St. Thomas Fort in Kollam, I recommend checking with local tourist authorities or official sources.