After headword and description with some equivalences, I give the section numbers in the Chronicon Lethrense where the place or person appears by name. On the following lines (if any), all the different specific forms in which these proper names appear in the text are listed. Some names are treated inconsistently, sometimes using Latin endings according to a particular declension and sometimes not -- such different versions of the same name are listed on different lines. Where a series of forms does fit into a Latin declensional pattern, such forms are all listed in the same line side by side. If a name (or version of a name) listed below does not have a declension number (DI, DII, DIII), be prepared for it to be conceptually in any case depending on context.
MSE = Phillip Pulsiano et al. (eds.), Medieval Scandinavia: An Encyclopedia
Brawel (plain in Sweden) [9]
Dacia = Dania (= Denmark) [1][2][3][5][6]
Danærigh (stone where kings are made) [2]
Danæwirchi (= Danevirke) [2]: MSE s.v. "Danevirke"; https://whc.unesco.org/en/list/1553; https://en.wikipedia.org/wiki/Danevirke -- Note new discoveries: an 8th century gateway in the Danevirke [Der Spiegel]
Dania (= Denmark) [1][2]
Falster (island) [1]
Feonia (= Fyn) (island) [1][2]
Hethæby (city in Jutland = Hedeby = Haithabu) [9]: https://whc.unesco.org/en/list/1553
Høkæbiærgh (mountain in Sialandia) [3]
Høkækøping (city in Sialandia) [3]
Hornshæræth (province of Sialandia) [7]
Jucia (Jutia) (= Jutland) [1][2]
Jutlandia (= Jutland) [6][9]
Laland (= Lolland) (island) [1][4]
Leshø (island) [5]
Lethra (city in Sialandia = Lejre) [1][3][4][7][8]
Maguncia (= Mainz) [2]
Møn (island) [1]
Roskilde ("Ro's spring" -- city built by Ro) [3]
Scania (coastal area, now in Sweden = Skåne) [1][2][8]
Sleswicensis (adj. "Schleswigian" - of Schleswig, an area of southern Jutland) [9]
Sculdælef (villa / hall?) in Hornshæræth) [7]
Sialandia (= Sjælland / Zealand) (island) [1][3][7]
Suethia (= Sweden) [1][4][5][9]
Thorhø (island where Thora, Rolf, and Helgi are buried) [4] [= Thorø]
Uppsala [1]
Withesleth (Sialand, Møn, Falster and Laland together) [1][2]
Ysæfjorth (inlet in Sialandia) [3]
Aki (brother of Haghbard) [8][9]
Asa (daughter of Olav) [9]
Athisl (king of Sweden) [4][5][7]
Augustus ("the first Caesar") [2] (cf. "Emperor"?)
Dan (son of Ypper, reigned as king in Withesleth at Lethra; father of Ro) [1][2][3]: Cf. Saxo Grammaticus 1.10 (only the name)
Dani (= the Danes) [2][5][6][7][8][9]
Dannia (Dan's wife) [3]
David (Biblical king) [1]
"The Emperor" (Imperator) [1] (cf. "Augustus"?)
Fritleff (from the North, became father-in-law of Rolf Kraki) [8][9]
Frothæ [with cognomen Largus] (son of Fritleff) [8][9]
Haghbard (brother of Aki) [8]
Haldan (son of Ro; father of Siwardus) [3][4][5]
Hamund (father of Aki and Haghbard) [8]
Harald [with cognomen Hildetan, "Wartooth"] [9]: MSE s.v. "Divine Heroes, Native," section (1); Saxo Grammaticus 7.10.4ff.; https://en.wikipedia.org/wiki/Harald_Wartooth; Battle of Bråvalla: https://en.wikipedia.org/wiki/Battle_of_Br%C3%A1vellir; https://spangenhelm.com/battle-of-bravalla/; Saxo Grammaticus 8.1.1ff.
Harold (= Harald Klak) [2]: Cf. Chron Rosk 1, 10
Helgi (son of Ro; father of Ursula, and by her, of Rolf Kraki) [3][4][5][7]
Hethæ (female standard-bearer with Harald Wartooth, then ruler of Dania) [9]: cf. Hetha in Saxo Grammaticus' account
Hiarwart (a "Teutonic" count of Scania, dependent of Rolf Kraki) [8]
Ingyald (son of Frothi) [9]: https://en.wikipedia.org/wiki/Ingjald
Jutones (= the Jutes; perhaps differentiated from the Jutenses who are simply the inhabitants of Jutland [Chron. Rosk.]) [2]
Læ (giant of Leshø) [5][6]
Lodowicus (= Louis the Pious) [2]
Nori (son of Ypper) [1]
Olav (son of Ingyald) [9]
Østen (son of Ypper) [1]
Raka (the "whelp" king imposed by Athisl) [5][7]
Ring (king of Sweden = Sigurd Hring, supposedly the father of Ragnar Lothbrok) [9]: https://en.wikipedia.org/wiki/Sigurd_Ring
Ro (son of Dan; father of Helgi and Haldan) [3] [= Hrothgar? https://en.wikipedia.org/wiki/Hrothgar] [Cf. two minor "Roe"s in Saxo Grammaticus 2.46-47, in roughly this family tree]
Rolf / "young Rolf" / Rolf Kraki (son of Helgi and Ursula) [4][7][8] [The story of Rolf has strong parallels in detail with Saxo Grammaticus (2.5.2ff.) and the vernacular Ynglinga Saga and Hrolfs saga kraka. A brief version in Sven Aggesen 1]
Rolfcarl / Rolf / "old Rolf" (a certain "baron" in Laland; father of Thora) [4]
Røth (resistance to Snyo) [6]
Scanienses (inhabitants of Scania) [8]
Sculd (daughter of Athisl and Ursula, sister of Rolf) [4][7][8]
Sialandenses (inhabitants of Sialandia) [8]
Siwardus [with cognomen Albus] (son of Haldan) [4]
Snyo (shepherd then king) [5][6][7]
Swærthing (his sons killed Frothi) [9]
Thora (daughter of Rolfcarl; mother of Ursula) [4] [In Saxo, her parentage is not given, but in Hrolfs saga she is the daughter of Olof queen of Saxony, and this encounter was his revenge for being rebuffed in marriage. The island is named Thorø.]
Ursula (daughter of Helgi and Thora) [4][7] [In Saxo and Hrolfs saga: Yrsa.]
Wysna (female standard-bearer with Harald Wartooth) [9]
Ypper (king in Upsala) [1]