The competition was open to School of Textiles and Design students.
Entries were narrowed down to five finalists before the winner was chosen.
Kaci said: “As a designer, there is nothing more fulfilling than knowing your work will be worn and appreciated by other people.”
The tartan was formally presented to America250 – the organisation coordinating celebrations the anniversary.
An initial limited run of commemorative scarves featuring the design will now be woven at Lovat Mill in Hawick.