List of all sites sorted by root-name (common alternative spellings in parentheses) where jars with incised Plus marks have been excavated {map grid coordinates in braces}:

1. Arad {M-55}
2. Azekah (Tell Zakariya) {H-42}
3. Beersheba (Tel Beer-sheba, or Tell es-Seba' {G-56})
4. Beit Mirsim (Tell Beit Mirsim; Debir or Kirjath Sepher?) {G-49}
5. Beth Shemesh (Ain Shems or Tell er-Rumeileh) {H-40}
6. Beth Zur (Khirbet et-Tubeiqa) {L-45}
7. Chephirah (Hirbet Kefire, or Kefireh, or Khirbet el-Kefirah) {L-38}
8. Ein Gev {Z-8}
9. Ekron (Tel Miqne or Khirbet el-Muqanna') {F-39}
10. Gath (Tell es-Safi or Tel Zafit) {E-42}
11. Gezer {G-37}
12. Gibeah (Tell el-Ful) {P-38}
13. Gibeon (el-Jib) {N-37}
14. Hazor {X-1}
15. Horvat Uza {N-43}
16. Ira (Tel 'Ira, Horvat el-Garra, or Khirbat al-Gharra) {I-56}
17. Jerusalem {P-39}
18. Kedesh (Qudeis) {O-15}
19. Lachish (Tell ed-Duweir) {F-46}
20. Megiddo {N-14}
21. Mevorakh {G-16}
22. Mesad Hashavyahu {A-35}
23. Nasbeh (Tell en-Nasbeh; Mizpah?) {O-36}
24. Qasile {D-29}
25. Rabud (Khirbet Rabud; Debir?) {J-50}
26. Ramat Rahel (Ramat Rachel; Khirbet es-Sallah; Netopha or Beth-Haccerem?) {O-41}
27. Timnah (Tel Batash) {G-39}
28. Tumuli (#5 & #6 in Amiran's Area "A" near Kiriat Menahem or Kiryat Menah'em) {N-40}

Total sites where before-firing cooking-pot (a.k.a. IHCP = Incised Handle Cooking Pot) handles have been found:  20

Total sites where after-firing Plus-mark (AFPM) handles have been found:  12

Note:  Many other sites exist where incised handles have been found; however, their type has not yet been confirmed.  The sites shown here as "Unconfirmed" have a very high probability of belonging to the AFPM group.  See "Ancient Contribution Jars" by G.M. Grena for additional info & references (BlogSpot version or WordPress version; same content at both websites).

Most excavation reports from the past century have not provided detailed descriptions of incised handles, typically labeling them as "potter's marks", & showing one or a few representatives.  In addition to the 2 major types presented on this page, many other varieties of marks (zigzags, checkerboards, depressions, strokes, letters) appear on a variety of jars (jugs, juglets, pots) in a variety of locations (handles, rims, bodies).  Here are the minimum quantities from each of the sites shown on the map above:

Note:  Whereas pre-fired incisions & seal impressions are rare & valuable to antiquities collectors, marks made after firing such as AFPMs are not nearly as important since they could easily be forged, so they bear no scientific value.