Find-A-Grave: Contains almost 120,000 memorials for people buried at Loudon Park, many with photos of the gravestones
Adopt a Confederate: Information, biographies, and photos related to the Confederate Hill section of Loudon Park (see here for a spreadsheet containing the records on this site)
Interment.net: Has a short list of burials at Loudon Park (see here for a spreadsheet containing the records on this site)
Billiongraves.com: Has over 700 burials listed, many with photos (see here for a spreadsheet containing the records on this site)
USGenWeb: Has a short list of burials at Loudon Park, including many photos and some transcriptions (see here for a spreadsheet containing the records on this site)
MDGenWeb: Has a short list of burials at Loudon Park (see here for a spreadsheet containing the records on this site)
FamilySearch: The LDS Family History Center in Ellicott City, Maryland, has microfilm copies of all burials at Loudon Park prior to 1986, sorted both by name and by plot, as well as deed records. If you are in the Baltimore area you can visit the Ellicott City location (hours and directions) or you can request that copies of specific films be sent to the Family Search Center nearest you ($). Better yet, you can use the digitized version, which FamilySearch finished in 2018. When you go to the FamilySearch page for the Loudon Park microfilm records, click on the camera icon in the "Format" column to see the digital version. UPDATE: The digitized microfilm records are now searchable! In some cases, you can click on the plot location and see all of the people buried in that plot.
Baltimore County Genealogical Society: The BCGS Library, located in Parkville, Maryland (hours and directions), has a notebook listing all burials at Loudon Park for those with surnames starting with "A" and "B". Apparently, the people who produced this book had a falling out after the first volume was published and were never able to finish the project. Fortunately, however, the microfilm that they purchased for the project is now permanently resident at the Ellicott City Family History Center (see above). See here for scans of this notebook and spreadsheets containing records derived from these scans.
Wikipedia
Loudon Park Cemetery: Corporate web site (mostly about how to obtain burial plots and services)
Department of Veterans Affairs: Information about Loudon Park National Cemetery, which is adjacent to, but not associated with, Loudon Park Cemetery. There is also a Find-A-Grave site for Loudon Park National Cemetery.
Adopt a Confederate: Information, biographies, and photos related to the Confederate Hill section of Loudon Park (see here for a spreadsheet containing the records on this site)
Interment.net: Has a short list of burials at Loudon Park (see here for a spreadsheet containing the records on this site)
Billiongraves.com: Has over 700 burials listed, many with photos (see here for a spreadsheet containing the records on this site)
USGenWeb: Has a short list of burials at Loudon Park, including many photos and some transcriptions (see here for a spreadsheet containing the records on this site)
MDGenWeb: Has a short list of burials at Loudon Park (see here for a spreadsheet containing the records on this site)
FamilySearch: The LDS Family History Center in Ellicott City, Maryland, has microfilm copies of all burials at Loudon Park prior to 1986, sorted both by name and by plot, as well as deed records. If you are in the Baltimore area you can visit the Ellicott City location (hours and directions) or you can request that copies of specific films be sent to the Family Search Center nearest you ($). Better yet, you can use the digitized version, which FamilySearch finished in 2018. When you go to the FamilySearch page for the Loudon Park microfilm records, click on the camera icon in the "Format" column to see the digital version. UPDATE: The digitized microfilm records are now searchable! In some cases, you can click on the plot location and see all of the people buried in that plot.
Baltimore County Genealogical Society: The BCGS Library, located in Parkville, Maryland (hours and directions), has a notebook listing all burials at Loudon Park for those with surnames starting with "A" and "B". Apparently, the people who produced this book had a falling out after the first volume was published and were never able to finish the project. Fortunately, however, the microfilm that they purchased for the project is now permanently resident at the Ellicott City Family History Center (see above). See here for scans of this notebook and spreadsheets containing records derived from these scans.
Wikipedia
Loudon Park Cemetery: Corporate web site (mostly about how to obtain burial plots and services)
Department of Veterans Affairs: Information about Loudon Park National Cemetery, which is adjacent to, but not associated with, Loudon Park Cemetery. There is also a Find-A-Grave site for Loudon Park National Cemetery.