National parks, known for their unique natural landscapes and biodiversity, offer significant potential as learning environments where real-world examples can bring abstract school subjects to life. Even though there have been a handful of studies exploring the potential use of national parks as appropriate locations for science education, education research focusing on mathematics in the national park context has been scarce. In this chapter, we aim to remedy this situation. More specifically, we investigate the role of national parks as out-of-school learning settings in teaching mathematics. We begin with a brief overview of national parks, the reasons behind their establishment, and the associations created to support them. Then we zero in on the educational potential of national parks as contexts for out-of-school learning of mathematics. We end the chapter with some sample mathematical activities that point towards how nature itself can transform abstract mathematical ideas into tangible experiences, highlighting the intrinsic structure, harmony, and beauty of mathematics.