In the late nineteenth century the U. S. Coast & Geodetic Survey undertook measurements to determine the nation’s physical shape with absolute accuracy through two triangulation networks, one stretching from coast to coast and another from Mexico to Canada. The north-south survey, known as the 98th Meridian Survey, passed through central Nebraska during 1898-1901, with angles turned at night from observation towers to lights on other towers many miles apart and distances between points computed mathematically by trigonometry. Because these triangulation computations required precisely measured base lines on the ground about every one hundred miles, one important base line measuring 5.127 miles was placed north of Page in 1900 on a southwest-to-northeast line. Its ends were marked with special monuments, and in 2007 a group of surveyors recovered them; the monument at this site once marked the northeast endpoint of the Page Base Line, about six miles northeast of Page.