| Sleswick-Holstone Schleswig-Holstein | |
| Boundland of Theechland | |
 Flag | |
| Ethel | Theechland |
| Headstead | Keel |
| Revetung | Allmean Theech |
| Other tungs | Low Saxish, North Frish |
| Inwonername | Sleswick-Holstoner |
| Lawmoot - Body - Rede-Foresitter |
Landday of Sleswick-Holstone Daniel Günther |
| Landswathe | 6,244 miles² |
| Befolking (2015) - Overall - Huddlemete |
2,858,71 4470 miles² |
Sleswick-Holstone (Theech & English: Schleswig-Holstein, Danish: Slesvig-Holsten,) is the northernmost of the 16 boundlands of Theechland, making up most of the sheedly heretog of Holstone and the southern bit of the former Heretog of Sleswick. Its headstead is Keel; other outstanding steads are Lübeck and Flensborough.
Also known in more dealmarked English as Sleswick-Holsatia, the Danish name is Slesvig-Holsten, the Low Saxish name is Sleswig-Holsteen, and the North Frish name is Slaswik-Holstiinj. Sheedly, the name can also forwise to a bigger field, holding both today Sleswick-Holstone and the former South Jutland Shire (Northern Sleswick) in Denmark.