(Mountains of the Holy Cross), mountains in Poland, the highest part of the Kielce-Sandomierz Uplands. The Świętokrzyskie Mountains are approximately 80 km long and, at Mount Łysica, reach an elevation of 612 m. They are composed of quartzites, graywackes, sandstones, and limestones, which are frequently overlain by unconsolidated deposits, including morainal deposits. Hill-and-ridge topography predominates, with cuestas in places. Oak and pine forests grow at the foot of the mountains, beech and fir forests higher up the slopes. Świętokrzyski National Park is set amid the highest areas of the mountains.