Step 1: Recall famous mural paintings of Kerala.
Kerala is renowned for its classical mural painting tradition, found in temples and palaces, depicting scenes from Hindu epics and mythology.
Step 2: Identify the largest mural painting.
Krishnapuram Palace in Kayamkulam, Alappuzha district, houses the Gajendra Moksham mural, which is considered India's largest single mural painting, measuring approximately 49 feet long and 14 feet high.
Step 3: Eliminate other palaces.
Kowdiar Palace, Kanakakkunnu Palace, and Hill Palace are famous palaces in Kerala but are not known for India's largest mural painting.
\[ \boxed{\text{Krishnapuram Palace}} \]