Lajos-forrás, Natural spring in Visegrád Mountains, Hungary.

Lajos-forrás is a spring on the Bölcső-hegy massif at 587 meters in the Szentendre area. Its 1908 stone basin, built by the Hungarian Tourist Association's "Péntekiek" group with architect Gabrinyi Sámuel, collects water that feeds the Jóvízű-patak. The spring is reached by marked trails and a small road ending at Lajosforrás.

The spring's name honours Baron Podmaniczky Lajos, who owned the land when the "Péntekiek" group of the Hungarian Tourist Association built the stone basin in 1908 with architect Gabrinyi Sámuel. Earlier, Serbs settled in the area from the early 18th century called it Dobrá voda, and the Hungarian equivalent Jóvíz-dűlő became an official place name. A tourist hostel operated beside the spring from 1947 to 2005.

Serbian settlers in the early 18th century called this water source Dobrá voda, a name that influenced the later Hungarian term Jóvíz-dűlő. The site preserves this linguistic heritage from its earliest residents.

The spring is accessible via Route 1114 from Szentendre, where a large bus turnaround serves visitors arriving by different means of transport. The stone pool design allows hikers to collect water in containers, though consumption is at each visitor's discretion.

A tourist hostel stood beside the spring from 1947 to 2005, and a wide bus turning circle was built before it so tour buses could reach the site. Weekend bus 868 from the Szentendre HÉV station to Dömör-kapu stops at Lajos-forrás from spring to autumn.