During the War of 1812, the people of Baltimore believed that the British would attack the city. Not knowing for sure when an attack would occur, they spent months preparing for it. Everything was made ready at Fort McHenry to defend Baltimore.
Major George Armistead, the Fort’s commanding officer, desired "to have a flag so large that the British will have no difficulty in seeing it from a distance."
In the summer of 1813, Armistead ordered a large garrison flag (30 feet by 42 feet) as well as with a smaller storm flag (17 feet by 25 feet) for the Fort. The job went out to a 37-year-old widow, Mary Pickersgill, a ship and signal flag maker. She labored for seven weeks with her 13-year-old daughter, Caroline, two nieces, 13-year-old Eliza Young and 15-year-old Margaret Young, a 13-year-old African-American indentured servant, Grace Wisher, and possibly her mother, Rebecca Young, who had taught her the trade. They pieced together strips of loosely woven English wool bunting then laid the whole flag out on the expansive floor of a brewery near Mrs. Pickersgill’s Pratt Street house, now the Star-Spangled Banner House museum. The flags were finished on August 19, 1813.
The larger of the two flags had stripes two feet wide, and stars 24 inches from point to point. At that time, it was the practice to add one star and stripe for each new state joining the Union. In 1814, the United States flag had 15 stars and 15 stripes.
The 30' x 42' flag was the one that Francis Scott Key saw on the morning of September 14, 1814. It inspired him to write the words to "The Star-Spangled Banner." Today this flag is displayed in the Smithsonian Institution's National Museum of American History, Washington, D.C. The smaller storm flag, which many historians believe was the flag that flew during the rainy bombardment, has been lost to history.