The results of 1657 speckle interferometric observations of double stars, made with the 26 inch (66 cm) refractor of the US Naval Observatory, are presented. Each speckle interferometric observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1111 mean relative positions and range in separation from 016 to 1699, with a median separation of 165. This is the 12th in a series of papers presenting measurements obtained with this system and covers the period 2005 January 3-December 29. Included in these data are 30 older measurements whose positions were previously deemed possibly aberrant but are no longer classified this way following a confirming observation. Sixteen of these systems have new orbital elements, which are presented here as well. For η Coronae Borealis (STF 1937) we determine masses of 1.207 and 1.077 M⊙ and an orbital parallax of 54.95 mas.
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