Many residents in Portland have driven past Mill Ends Park dozens, nay hundreds of times, and never even noticed it was there. Deemed the worlds smallest city park in 1976 by the Guinness Book of World Records, the park is merely two feet wide, and lies in the median of the heavily trafficked Natio Parkway.

From the Portland Parks and Recreation website: "In 1946, Dick Fagan returned from World War II to resume his journalistic career with the Oregon Journal. His office, on the second floor above Front Street (now Naito Parkway), gave him a view of not only the busy street, but also an unused hole in the median where a light pole was to be placed. When no pole arrived to fill in this hole, weeds took over the space. Fagan decided to take matters into his own hands and to plant flowers."

Fagan wrote a very popular column about this park called Mill Ends, which is a lumber term for rough irregular ends of boards from lumber mills. The park was dedicated on St. Patrick's Day in 1948 by Fagan who wrote about the trials and tribulations of the park's head leprechaun Patrick O'Toole, and according to Fagan the only group of leprechauns to establish a colony west of Ireland. He also claimed to be the only person who was able to see these leprechauns, and therefore had the exclusive scoop.

In Fagan's account of Mill Ends Park's origin, supposedly Fagan "looked out the window and spotted a leprechaun digging in the hole. He ran down and grabbed the leprechaun, which meant that he had earned a wish. Fagan said he wished for a park of his own; but since he had not specified the size of the park in his wish, the leprechaun gave him the hole."

Fagan passed away in 1969, and Mill Ends officially became a city park on St. Patrick's Day in 1976. The park continues to be the site of inventive St. Patrick's Day festivities to this day.

The park has seen many renovations over the years, for a while it was home to a small swimming pool and diving board for butterflies, many statues, and a miniature Ferris wheel which was delivered by a full sized crane.

In 2006 the park was temporarily moved (7 feet) while construction on the Natio Parkway took place. It was replaced on March 16, 2007 to a full St. Patrick's Day celebration complete with bagpiper's, Irish folk music, and Dick Fagan's wife Katherine and family proudly in attendance.