What scientist was responsible for surveying the land now known as Washington D.C.?

The scientist responsible for surveying the land that is now Washington D.C. was Pierre Charles L'Enfant. In 1791, he was commissioned by President George Washington to design the new capital city. L'Enfant's plans included broad avenues, public parks, and a symmetrical layout, which have influenced the city's design to this day. His vision and work laid the foundation for the capital's development.