Full 1:250.000 DMZ map from 1969.  (Click on the image to get up a high-resolution image.)  Source: Wikimedia.

A  1:1.000.000 DMZ USA Army map from 1964 over the DMZ/Korean boundary.  Source: Wikimedia.

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Fragment from the 1969 map showing the Joint Security Area.  Source: Wikimedia.

A fragment from the 1964 map. Notice the neutral waters in the bay area.  Source: Wikimedia.

JSA region overview. The zone between the lines is the North Korean part of the DMZ. The sourthern or eastern line represents the Military Demarcation Line (MDL) which is a de facto North Korean - South Korean boundary.

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Close-up of the upper orthomap. We see that the Armistice building is located inside the DMZ.

The Pyongyang - Seoul highway ends just before the North Korean JSA information Center. 
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The North Korean JSA part of DMZ makes a semi-enclave only connected to the rest of the North Korean DMZ by a 40 m wide and 130 long corridor.  The original Pyongyang - Seoul main road went over the Bridge of No Return.  Now it is only technically possible to drive through the JSA over the 72-hour Bridge; as there are put road obstacles at the southern bridge. The 72-hour Bridge got its name since it was built during 72 hours after the Bridge of No Return incident.
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The road between the countries goes over the Conference row; simply between the buildings.  
MDL position inside the most frequently used conference shed is 37°57'21" N  126°40'37" E.
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