Charles Ellicott Commentary 2 Chronicles 26:9

"Moreover Uzziah built towers in Jerusalem at the corner gate, and at the valley gate, and at the turning [of the wall], and fortified them." — 2 Chronicles 26:9 (ASV)

Built towers. — To defend the approaches.

At the corner gate. — Over, that is, commanding the gate (2 Chronicles 25:23). Probably the north-west corner of the city wall.

The valley gate. — Syriac, “the west gate.” In the western wall, this is the modern Jaffa gate. These two towers protected the most exposed points of the capital.

At the turning of the wall. — Over the angle (ha-miqçôa ̒), that is, on the eastern side of Zion, at a bend in the wall. This tower defended both Zion and Moriah against attacks from the south-east. (Nehemiah 3:19–20; Nehemiah 3:24–25)

And fortified them. — Literally, made them (the gates) strong.

Or rather, perhaps, he made the towers strong, that is, put them in a posture of defence. (Compare to 2 Chronicles 11:11)

The margin is wrong.

The Syriac version reads, “girded (or bound) them at their corners with clamps (glîdê, that is, κλεῖδες) of iron.”