From Google Translate:
The emigrant database of the two Rhineland-Palatinate state archives is currently based primarily on the evaluation of sources on emigration to America in the period from 1815 to 1914. Occasional entries beyond this are due to the file duration or file structure. The very different histories of the areas, for the transmission of which the two archives are responsible, leads to differences in the emigration transmission and in the selection of files.
Due to the Prussian structure of the administration of the Rhine Province, there is a central record on emigration from the district governments, structured according to destinations (continents or countries), in the Koblenz state archives. Therefore, the focus here is currently on the evaluation of this extensive group of files, the "emigrations to America" for the period mentioned above. In the Speyer State Archives, responsible for the then Bavarian Palatinate and Rheinhessen, there is no homogeneous record of emigration to be found. The corresponding files are often not limited to a specific emigration destination and also contain emigrations to other German territories, which are then also recorded.
Only the documents relating to emigration from Bavaria are evaluated, as the “Emigration Proofs” from the Hessian State Archives in Darmstadt are a suitable research tool for legal emigration from the Grand Duchy of Hesse-Darmstadt and thus also for Rheinhessen. These can be called up online via the Hessian archive information system (Arcinsys) at: arcinsys.hessen.de/arcinsys.
The inclusion of data in the emigrant database is an ongoing process (56,089 records, as of December 31, 2020) It is therefore also possible that you will not receive any research results for the name or place you are looking for because the relevant files have not yet been evaluated. In these cases, we recommend that you send an inquiry to the responsible archive. Each person is recorded with their own data set. As a rule, surname, first name, date of birth (or age), place of residence, district, date of emigration (application, discharge, passport issue, embarkation) and destination are recorded. In our virtual reading room "Apertus" you can search for emigrants from the area of today's Rhineland-Palatinate and its predecessor territories (e.g. also Wetzlar). There you will also find help texts on using the emigrant database.