Madlum cave/river can be found in Mount Manalmon, San Miguel, Bulacan. This river is a snaky river with shallow clear water along the left side deepening to the right side. It possesses novel landscapes, including those of Madlum River, whose rock formations compensate for an otherwise unremarkable environ. Also, nearby sites such as the Bayukbok Caves (a 2-hr exploration from the River) and Madlum cave can be coupled with a trip to Mt. Manalmon to maximize the Biak-na-Bato experience. Also, complementing Mt. Manalmon is another elevated ground called Mt. Gola; instead of turning right at the bifurcation, going left would lead to this peak, which is also a good vantage point.
Going here can last 2 hours coming from Brgy. Kamias.. It's very tiring because of long hour trip but when you got there, it will fade away. I remembered the last time we visited this place we need to walked , go upstairs going to the statue of virgin Mary and passed through the cave.. It's so very dark inside as in we cannot see everything so we better need to bring a flashlight to lighten our way. After passing through the cave we can now enjoy swimming in the river.. :) It's very refreshing because of the clean and cold water. There are parts that so very deep and place that are shallow. The formation of rocks here are awesome. The most enjoyable part for me there is when i need to climbed the rock and dive from there. It's frightening at the first time but later on it's very addictive :D I also remembered that there are some foreigners visiting that place. Camping may be done either after the river, or within the summit area. 
This place is very beautiful and relaxing so you better try to visit this :))
