NY 149 was truncated eastward to the southern terminus of its overlap with US 4 south of Fort Ann. The change lasted for roughly 15 years before the highway was reextended westward to NY 9L in the mid-1950s. It was extended again in the late 1950s to follow a pre-existing, unnumbered roadway west to US 9 in the Queensbury hamlet of French Mountain. NY 149 was altered once more to meet the new I-87 at exit 20, resulting in a short overlap with US 9.