| Hormersdorf Observatory | Hormersdorf | — |
| Hoyerswerda observatory | Hoyerswerda | — |
| Huenfelden Observatory | Hünfelden | — |
 Höfingen observatory | Leonberg | — |
| Immanuel Kant observatory | Limbach-Oberfrohna | — |
| Inastars observatory | Potsdam | — |
 Institute of Avian Research "Vogelwarte Helgoland" | Wilhelmshaven | — |
 Instituto de Astrofísica de Potsdam | Potsdam | — |
 Instituto de Cálculo Astronómico | Heidelberg | — |
| Irmtraut observatory | Irmtraut | — |
| Isarwinkel observatory | Bad Tölz | — |
 Jena Observatory | Jena | — |
 Johann-Kern-Sternwarte Wertheim | Wertheim am Main | 275 m |
| Johannes-Kepler observatory | — | — |
| Josef Bresser Observatory | Distrito de Borken | — |
 Karlsruhe Observatory | Karlsruhe | 125 m |
| Karrenkneul observatory | Calden | — |
 KATRIN | Karlsruhe | — |
| Kiel Observatory | Kiel | 10 m |
| Knielingen Observatory | Karlsruhe | — |
| Koeditz observatory | Köditz | — |
| Köln observatory | Colonia | — |
| Laupheim Planetarium | Laupheim | — |
| Leipzig observatory (since 1861) | Leipzig | — |
| Lenkerbeck observatory | Essen | — |
 Lilienthal Observatory | Lilienthal | — |
 Lindenberg Meteorological Observatory | Brandemburgo | — |
| Lohbach Observatory | Dortmund | — |
 Lohrmann Observatorium | Dresde | 140 m |
| Lohrmann observatory | Dresde | — |
 Lübeck observatory | Lübeck | 10 m |
| Maidbronn observatory | Rimpar | — |
 Mannheim Observatory | Mannheim | — |
| Marburg observatory | Marburgo | — |
| Marienburg observatory | Hildesheim | — |
| Marine Observatory | Hamburgo | — |
| Marl observatory | Marl | — |
| Mauren Valley observatory | Holzgerlingen | — |
| Meschede observatory | Meschede | — |
 Meteorologisches Observatorium Potsdam | Potsdam | — |
| Moorwarfen observatory | Jever | — |
| Mueggelheim observatory | Parada de tranvía Müggelheimer Straße/Wendenschloßstraße, Berlin | — |
| Muensterschwarzach Observatory | Schwarzach am Main | — |
| Mundenheim observatory (1907-1913) | Ludwigshafen | — |
| Munich observatory (1819-1938) | Múnich | — |
 Mühlenturm | Rees | — |
 Neschwitz Bird Observatory | Neschwitz | — |
 Neumünster public observatory | Neumünster | 26 m |