The cache is placed in the USGS Madison Quadrangle in Yolo County, California. It is the 29th in our series of caches placed near the site for which a USGS 7½-minute quadrangle map is named.
Madison is small community located at N 38º 40’ 45” W 121º 58’ 06”. According to Wikipedia the original name of the community was Cache Creek and a post office with that name was established in 1852. The name of the town was changed to Madison in 1877. The cache is located north of town on CR 89.
The quadrangle boundaries are:
N 38º 37’ 30” and N 38º 45’ 00”
W 121º 52’ 30” and W 122º 00’ 00”.
The United States Geological Survey (USGS) has many missions. At one time, a major mission of the USGS was the supplying of topographic maps of the United States on several scales. Our cache series is based on the 7½-minute quadrangle series.
The term quadrangle is used, instead of quadrilateral or rectangle, because the sides of these blocks are curved. The USGS divided the United States into quadrangles that are 7½ minutes by 7½ minutes. Since a degree is divided into 60 minutes, a quadrangle one degree by one degree contains 64 of these quadrangles.