Pu'u o Mahuka Heiau State Monument, Ancient religious temple site in North Shore of Oahu, United States.

Puʻu o Mahuka Heiau is the largest heiau on Oʻahu, covering 2 acres on a hilltop above Waimea Bay and Waimea Valley. It consists of three walled stone enclosures; the highest may date to the 17th century, the two lower ones perhaps to the 18th. The upper platform appears to have served as a luakini heiau, a temple for success in war.

Construction of the temple occurred in the 1600s, establishing it as a major religious center that functioned until the traditional Hawaiian religion was abolished in 1819. The site became a center of power and influence under successive religious leaders who shaped local decisions and military strategies.

The name Puʻu o Mahuka means "Hill of Escape"; legend says Pele leaped from here toward Molokaʻi. At the start of Makahiki, the four-month Hawaiian New Year, an observer at Kaʻena Point saw the Pleiades rise just above the heiau after sunset.

The site is open to the public during daylight hours and located at the end of a quiet residential road with available parking nearby. Visitors should wear sturdy footwear since the stone structures are uneven and the hillside terrain includes rocky sections that require careful footing.

The site once served as a communication hub using signal fires to transmit messages across ocean channels to distant islands within the archipelago. This sophisticated system allowed leaders to coordinate activities and share urgent information without physical travel between settlements.