The Green-Meldrim House stands on the northwest corner of Madison Square. It was built in 1853 for Charles Green, an English-born cotton merchant who arrived in 1833 and built one of the most successful cotton firms in antebellum Savannah. New York architect John Norris designed it, at a cost of about $93,000. It is among the finest Gothic Revival houses in the South, with a stuccoed brick exterior, oriel windows, lacy cast iron, a crenellated parapet and an iron entrance portico believed to be unique in the country. Inside it keeps its original woodwork, plaster and a freestanding staircase.

When General William T. Sherman took Savannah in December 1864, Green offered him the house, and Sherman made it his headquarters until early February 1865. From here he telegraphed President Lincoln offering the city 'as a Christmas gift,' with 150 heavy guns and about 25,000 bales of cotton. Much of the cotton, Wikipedia notes, belonged to Green himself. On January 12, 1865, in this house, Sherman and Secretary of War Edwin Stanton met twenty Black Baptist and Methodist ministers, including Garrison Frazier, Ulysses L. Houston and William Gaines. That meeting, later called the Savannah Colloquy, led directly to Special Field Orders No. 15, the 'forty acres and a mule' order. Susie King Taylor, who escaped slavery and became the only woman to publish a memoir of service in the Civil War, later worked for Mrs. Charles Green.

In 1892 Judge Peter Meldrim bought the house. In 1943 his heirs sold it to St. John's Episcopal Church next door, which uses it as its parish house. It was named a National Historic Landmark in 1976, and the church offers guided tours on most days for an admission fee.