The phrase strongholds of… Judah
refers to the fortified cities or defensive structures in the territory of Judah. These were places throughout the land that had been fortified to withstand external aggression. In times of danger or conflict the people of Judah would seek refuge in them. The fact that these have been broken down and destroyed by God's wrath symbolises the extent of the destruction and devastation that befell the region. As the Babylonians invaded the country, of these fortified cities, only Lachish and Azekah remained standing at one stage (see Jeremiah 34:7). Once these strong cities were overwhelmed, the land was defenceless.1
2 The Lord has swallowed up without mercy all the habitations of Jacob; in his wrath he has broken down the strongholds of the daughter of Judah; he has brought down to the ground in dishonor the kingdom and its rulers.