Brandegee was born on February 16, 1843, in
Berlin, Connecticut. From 1862 to 1864 he served in the Connecticut Artillery and later decided to become an engineer. He got his degree in engineering from
Sheffield Scientific School but then pursued botany after he participated at some classes with
Daniel Cady Eaton in
Yale University. When he graduated from there, he became a
county surveyor and city engineer at
Canon City, Colorado where in free time he also collected certain species of plants. He was accustomed with
John H. Redfield and
Asa Gray the later of which suggested him to join
Ferdinand V. Hayden's expedition to southwest
Colorado and
Utah where he will use his surveyor skills as well as botanical. He was hired as a railroad surveyor in both
Arkansas and
New Mexico and continued with plant collecting. Later on, he was hired at the
Northern Transcontinental Survey and created a map of
Adirondack region. On his journey he visited
Santa Cruz and
Santa Rosa Islands on one of which he collected wood for
Charles Sprague Sargent. ==Work, marriage and publications==