The coat of arms in the center of the flag was adopted on January 17, 1777. It depicts a shield of horizontal green, blue and white stripes. On the stripes is a sheaf of wheat, an ear of corn, and an ox standing on grass, all representing Delaware's agriculture. Above the shield is a sailing ship. Supporting the shield are a farmer on the left and a soldier on the right. The state motto, below the shield, reads "Liberty and Independence". These symbols are also included on the seal of Delaware.
The current flag was adopted on July 24, 1913. During the American Civil War, regiments from Delaware flew a flag which was similar to the state coat of arms on a field of blue.
In 2001, the North American Vexillological Association (NAVA) surveyed its members on the designs of the 72 U.S. state, U.S. territorial and Canadian provincial flags. NAVA members chose the Delaware flag as the 20th worst flag in the running, choosing it to be 52nd of the 72.
Delaware State Flag Symplistic Proposal. The shield in the middle is the shield of liberty, and the plant symbolizes agriculture. The parallelogram is a crop plot. By Ed Mitchell. 2013.
Updated Delaware state flag proposal by Ed Mitchell. 2016.
Delaware flag proposal by Arminius13
Delaware flag proposal by Achaley.
DE flag proposal "5thEye"
Delaware Flag Proposal by TheMaster001
Delaware Flag Proposal by TechMountenDew
The horizontal bars are taken from the State Seal, and buff diamond from the current flag. Delaware became the first State to ratify the US Constitution on December 7, 1787; references to this historic date are concealed in the proportions of the elements of this flag design: each bar has dimensions 87x17, for the year 1787, while the mid-points of each side of the diamond constructs a 12x7 rectangle, which references the date December 7. By Libervurto.
Delaware flag proposal by ColinHarkins.
Blue Hen State 1 by Newresnow
The Blue Hen State 2 by Newresnow
Up-Dated color set to reflect better the intended uniform colors. Design by Rotten Ali.
DE flag proposal by Dean Thomas. Armorial Banner of the State COA
Delaware flag proposed by Ken Morton - The 'Colonial Blue' of this flag represents Delaware's past, while the white symbolizes hope for the future. The three diamonds on the shield represent the three counties that make up the state, while also referencing the diamond-shaped field on the current state flag.
Delaware - Three Counties. Posted by Ken Morton
This was my original design for a Delaware state flag. I like the simplicity of a bicolor. The colonial blue field looks back to the past. The white field represents hope for the future via a tabula rasa. Posted by Ken Morton
I originally posted and proposed this design as a new flag for my home state of Connecticut, but the more I look at it, the more I see it as a better fit for the state of Delaware. Posted by Ken Morton
Utilizes the same primary colors of the existing flag (buff and gold). Three parallel stripes represent the 3 counties, with the diamond located off-center between. Will look good displayed both horizontally and vertically.
My version of the flag by ColinHarkins. The flag simplifies the design of the current flag, updates the colors to the state colors of blue and buff, and puts a singe star in the center to signify Delaware’s status as the first state. Posted by Preston Knapp 
Proposal for a flag for Delaware. Colors and basic layout taken from the shield, as are the cow and the stars. The golden discs represent the bushel of wheat and the corn. The many tiny stars are represented by three larger stars. By Qaz Dec 2019 (details)
Proposal "less is more" for a flag for Delaware. Just take all the lettering and emblems off the existing flag, and you have a unique flag. By Qaz Dec 2019 (details)
Proposal for a flag for Delaware. The design of this flag is identical to my other "less is more" design, but instead of using the pastel colors from the current flag it uses their "hard" color equivalents. By Qaz Dec 2019 (details)
Part of a series of fifty state flag designs, all in blue and white. (Posted by Ken Morton)
Proposed designs that feature or suggest the Swedish flag are commemorating New Sweden, a short-lived colony of Sweden that existed between 1638 and 1655. The colony's capital was in present-day Wilmington, Delaware, and settlements associated with it stretched along the Delaware River into parts of the modern states of Pennsylvania and New Jersey. The colony was short-lived, but the period of Swedish rule sets Delaware apart from other states and is still celebrated as part of the state's history and identity. The current flag of Wilmington is composed of the city seal on the Swedish flag. In 2013, the Swedish royal family visited Wilmington to commemorate the 375th anniversary of New Sweden's founding.