New York City has been implementing the watershed protection program based on the concept of Payment for Ecosystem Services for over 20 years. In this program, the Agricultural Conservation Easement (ACE) is used to designate farmland that provides a secure sustainable supply of ecosystem services. Clarifying the advantages and disadvantages of ACE will help give us valuable insight into its applicability as a Japanese conservation tools. We conducted a study that outlines the agricultural conservation easement (AEC) process, clarifying the characteristics of ACE as the system for sustainable stewardship and as the conservation tool tied to the development in urban centers. The results suggest that conservation system for sustainable supply of Ecosystem Services from farmland has several requirements: 1) a farmland appraisal system that takes into account the farming plan of the individual parcel, 2) technical support for farming viability in addition to easement payments, 3) a strategy based upon the purchase of continuous small farmlands is also important in order to enhance the sustainability of Ecosystem Services in the region as a whole.