The Flag of Northampton, Massachusetts, designed in 1988 and described as follows--
Proportions: 3:5
Formal description: On a dark green field, a medium blue stripe with white fimbriations, running from the upper fly to the lower hoist and forming a "U" shaped curve in the lower fly; placed in the center of the curve and with its point facing to the fly, a gold feather. 
The symbolism is described as follows:[1]
The green field has multiple meanings. First, it represents one of the city's nicknames, "The Meadow City," and recalls its agricultural past...Green also represents
the many verdant areas within the city, especially, Child, Laurel and Look Parks, and is indicative of the future vitality and growth of Northampton... The blue stripe with white fimbriations represents the Connecticut River, New England's longest. The shape of the stripe indicates the unique configuration of the river which occurs in Northampton. The river forms a very sharp curve called the "Ox Bow," as it reminded the early settlers of the bow in an ox yoke... The feather, like the other symbols, has several meanings. It signifies the original inhabitants of the area, the Nonotuck Indians. A single eagle, hawk or turkey feather in a Nonotuck brave's headband was a mark of honor, as it showed he took the life of an enemys. The feather, shaped to look like the quill pen, also represents the statesmen of Northampton, most notably Caleb Strong, Governor of Massachusetts and a delegate to both the Massachusetts and United States Constitutional Conventions. It is also indicative of Calvin Coolidge, Mayor of Northampton, Governor of Massachusetts and 32nd President of the United States. The feather is placed between the curve of the stripe as if it were in an ink well. 

↑  (1988-11). "City Flags: Northampton, Massachusetts". NAVA News XXI (6): 6-7. North American Vexillological Association. Archived from the original on 2017 February 14. Retrieved on 2017 October 26.
Design from City Flags: Northampton, Massachusetts, by James Craft, 1988. Colors from CRW Flags, albeit their photo shows the flag upside-down (see description)
Designed by Chartpak of Leeds, Massachusetts