The National Park Service (NPS), in cooperation with the National Capital Planning Commission (NCPC) has prepared this Environmental Assessment (EA) to evaluate a range of alternatives for the enhancement and improvement of the visitor screening at the Washington Monument (the Monument) in Washington, D.C. The National Mall is a highly recognizable space and one of the most significant historic landscapes in the United States, extending east to west from the U.S. Capitol building to the Potomac River and north to south from Constitution Avenue, NW to the Thomas Jefferson Memorial. The Washington Monument is the central point of the National Mall, placed at the intersection of two significant axes between the U.S. Capitol and the Lincoln Memorial to the east-west and the White House to the Jefferson Memorial to the north-south. The Washington Monument is made up of a stone masonry obelisk set within a circular granite plaza and flanked by large turf expanses. As the primary memorial to the nation's first president, the Monument is one of the most prominent icons in the nation and is toured by approximately one million visitors annually with millions more visiting the surrounding grounds. Its popularity, combined with its status as an icon, makes it a potential target for terrorist attack. A permanent perimeter vehicular barrier system was completed with landscape improvements in 2006. The visitor screening improvement project is needed because the existing visitor screening station, constructed at the Monument's base in 2001, was intended to be temporary and requires replacement to meet the long term security and cultural resource management requirements at the Monument. In 2002, the NPS completed a design for the Washington Monument Permanent Security Improvements including a comprehensive landscape solution for perimeter vehicular barrier system and a new screening facility. However, only the vehicular barrier system was installed. This project revisits the feasibility of a new entrance and visitor security screening facility. This EA presents a range of alternatives to improve the security and visitor flow at the Washington Monument in a manner that preserves the character and visitor experience of the Washington Monument and Grounds. Alternative C, a new screening facility on the Plaza in the same location as the existing temporary facility, is the NPS preferred alternative. Implementation of this alternative would result in long-term beneficial impacts to visitor use and experience from the improved aesthetics of the screening facility. There would also be long-term beneficial impacts to public safety and park management and operations. There would be long-term negligible adverse impacts to soils and long-term minor adverse impacts to visitor use and experience from congestion on the Plaza and the continued obstruction of the original view of the Monument's intersection with the Plaza on the eastern face. There would be long-term moderate adverse impacts to visual resources and cultural resources. However, due to the facility's design and ability to be removed, there would be long-term beneficial impacts to visual resources. There would be short-term negligible adverse impacts to soils and short-term minor adverse impacts to public safety, park operations and management, and cultural resources resulting from construction activities and the disruption of the Monument Plaza. There would be short-term moderate adverse impacts to visitor use and visual resources due to the closure of the project area during construction.