2nd Battalion, 1st Marines took over the defense of Con Thien in mid-December.
During the Christmas truce period the Battalion added 11 bunkers and dug a new trench along the forward slope.
The troops then sandbagged existing bunkers with a "burster layer" in the roofs, usually consisting of airfield matting to burst delayed fuse rounds.
They then covered the positions with rubberized tarps to keep the water out.
By the end of the year, all of the new bunkers had been sandbagged and wired in with the new razor wire.
During January the PAVN kept up sporadic fire on the base, firing for 22 of 31 days with each barrage averaging about 30 rounds.
The artillery fire gradually destroyed the minefield and bunkers protecting the northwest of the base, causing regular casualties.

The PAVN 803rd Regiment had relieved the 90th Regiment in the positions facing Con Thien and began to launch regular small scale probes of the Marine defenses.
On the night of 14 January, the PAVN tripped a mine and one soldier was left in the minefield; the PAVN made two attempts to rescue their wounded man, eventually succeeding under cover of small arms, recoilless rifles and mortars.
On 22 January, around midday the PAVN bombarded Con Thien with 100 rounds of 82mm mortar, followed by 130 rounds of 152mm shells.
1/4 sustained 2 killed and 16 wounded.
Thirty minutes later, about 1 km north of the base, Companies F and G encountered a PAVN Company which withdrew under cover of 60mm mortar fire; two Marines were killed and 8 wounded for 3 PAVN killed.

In late January, with increasing PAVN pressure on Khe Sanh Combat Base and Route 9, 1st Battalion 9th Marines was transferred to Khe Sanh and 3rd Battalion 4th Marines was moved to the Lancaster area of operations.
2nd Battalion 4th Marines was assigned to take over the 3/4's area of operations northeast of Con Thien, and on 27 January, HMM-361 landed the first units near C-2; by the end of the day the entire battalion was deployed.

On 29 January a Marine observer at Con Thien using a Starlight Scope spotted a PAVN convoy moving about 1 km north of the Ben Hai River and called in artillery air strikes.
The PAVN responded by launching five SAM-2 missiles on the attacking aircraft, which proceeded to destroy both the convoy and the SAM site.

By the end of January the defensive positions on the trace line, including C-2, C-2A and Con Thien (A-4), were largely complete, although there was abundant evidence of continued PAVN infiltration across the DMZ.

The Tet Offensive was little noticed at Con Thien and elsewhere along the DMZ; rather it was just the same fighting that had been going on for the previous weeks and months.
There was no Tet Truce here, but nor was there a sudden PAVN thrust through the DMZ or frontal assault on Khe Sanh as MACV had expected.

The PAVN continued to pressure the Marines particularly around the A-3 strongpoint between Con Thien and Gio Linh.
On 3 March, Lima Company, 3rd Battalion 3rd Marines, occupying an outpost on Hill 28 just north of the A-3, intercepted a PAVN battalion attempting to infiltrate the Marine positions.
The PAVN encircled the Marines and were only driven back by airstrikes and Huey gunship runs.
One Marine was killed and thirteen wounded while killing over 100 PAVN.
On 16 March, Mike Company, 3/3 Marines and Charlie Company, 1/4 Marines clashed with another battalion-sized PAVN force.
The two Marine companies called in artillery and air upon the PAVN, the bulk of which disengaged, leaving a company behind to fight a rearguard action.
PAVN artillery from north of the DMZ answered the American supporting arms with a 400-round barrage of its own on the Marines.
Marine casualties were two KIA and nine wounded for 83 PAVN killed.
For the entire month in Operation Kentucky, 9th Marines reported over 400 enemy dead while Marine casualties were 37 KIA and more than 200 wounded.

On 22 May a patrol from Company A 1/4 Marines ran into a PAVN force east of Con Thien.
1/4 Marines attacked east from Con Thien, while 3/3 Marines attacked west from Strongpoint A-3.
3/9 Marines we
2nd Battalion, 1st Marines took over the defense of Con Thien in mid-December. During the Christmas truce period the Battalion added 11 bunkers and dug a new trench along the forward slope. The troops then sandbagged existing bunkers with a "burster layer" in the roofs, usually consisting of airfield matting to burst delayed fuse rounds. They then covered the positions with rubberized tarps to keep the water out. By the end of the year, all of the new bunkers had been sandbagged and wired in with the new razor wire. During January the PAVN kept up sporadic fire on the base, firing for 22 of 31 days with each barrage averaging about 30 rounds. The artillery fire gradually destroyed the minefield and bunkers protecting the northwest of the base, causing regular casualties.
The PAVN 803rd Regiment had relieved the 90th Regiment in the positions facing Con Thien and began to launch regular small scale probes of the Marine defenses. On the night of 14 January, the PAVN tripped a mine and one soldier was left in the minefield; the PAVN made two attempts to rescue their wounded man, eventually succeeding under cover of small arms, recoilless rifles and mortars. On 22 January, around midday the PAVN bombarded Con Thien with 100 rounds of 82mm mortar, followed by 130 rounds of 152mm shells. 1/4 sustained 2 killed and 16 wounded. Thirty minutes later, about 1 km north of the base, Companies F and G encountered a PAVN Company which withdrew under cover of 60mm mortar fire; two Marines were killed and 8 wounded for 3 PAVN killed.
In late January, with increasing PAVN pressure on Khe Sanh Combat Base and Route 9, 1st Battalion 9th Marines was transferred to Khe Sanh and 3rd Battalion 4th Marines was moved to the Lancaster area of operations. 2nd Battalion 4th Marines was assigned to take over the 3/4's area of operations northeast of Con Thien, and on 27 January, HMM-361 landed the first units near C-2; by the end of the day the entire battalion was deployed.
On 29 January a Marine observer at Con Thien using a Starlight Scope spotted a PAVN convoy moving about 1 km north of the Ben Hai River and called in artillery air strikes. The PAVN responded by launching five SAM-2 missiles on the attacking aircraft, which proceeded to destroy both the convoy and the SAM site.
By the end of January the defensive positions on the trace line, including C-2, C-2A and Con Thien (A-4), were largely complete, although there was abundant evidence of continued PAVN infiltration across the DMZ.
The Tet Offensive was little noticed at Con Thien and elsewhere along the DMZ; rather it was just the same fighting that had been going on for the previous weeks and months. There was no Tet Truce here, but nor was there a sudden PAVN thrust through the DMZ or frontal assault on Khe Sanh as MACV had expected.
The PAVN continued to pressure the Marines particularly around the A-3 strongpoint between Con Thien and Gio Linh. On 3 March, Lima Company, 3rd Battalion 3rd Marines, occupying an outpost on Hill 28 just north of the A-3, intercepted a PAVN battalion attempting to infiltrate the Marine positions. The PAVN encircled the Marines and were only driven back by airstrikes and Huey gunship runs. One Marine was killed and thirteen wounded while killing over 100 PAVN. On 16 March, Mike Company, 3/3 Marines and Charlie Company, 1/4 Marines clashed with another battalion-sized PAVN force. The two Marine companies called in artillery and air upon the PAVN, the bulk of which disengaged, leaving a company behind to fight a rearguard action. PAVN artillery from north of the DMZ answered the American supporting arms with a 400-round barrage of its own on the Marines. Marine casualties were two KIA and nine wounded for 83 PAVN killed. For the entire month in Operation Kentucky, 9th Marines reported over 400 enemy dead while Marine casualties were 37 KIA and more than 200 wounded.
On 22 May a patrol from Company A 1/4 Marines ran into a PAVN force east of Con Thien. 1/4 Marines attacked east from Con Thien, while 3/3 Marines attacked west from Strongpoint A-3. 3/9 Marines we
Con Thien