I think Jean Paul Faguet should be able to answer your question. 

Indeed, I also could not find any area data in the National Statistics website.

Francisco: I've gone through Faguet's dataset, but he did not use surface area (and therefore population density) as one of his variables. I've emailed him directly to ask, and hope to hear back.

Walter: That's an interesting comment. It seems there are no limits to the size of Bolivian municipalities. The smallest municipality has a population of 509. But there are also some very big ones, particularly in the sparsely populated Amazon regions.

It exist the:

INE-MDSP-COSUDE; Atlas Estadístico de Municipios; CID; La Paz; 1999.

There you can find those areas.

Personally I have the book on my hands, if you need something more... 

Sorry, that information don't exist on that book. There you can get information of "province surfaces". 

I have a few atlases (including a very good one written by UNDP), but none of them give municipal surface area data.

I have tried looking in Wikipedia. Sometimes in German and other language pages for municipalities, the information is there. But ... it often doesn't match the information in other languages (e.g. Italian data doesn't match Dutch data). So I'm hesitant to try to use what I found there. None link to an authoritative source.

Dear Miguel, I have the data in excel with an accreditation from a functionary of the municipality of La Paz, please give me your e-mail adress for resending to you the complete e-mail with instructions.

To begin, I don’t think any of what I found is exactly what you were looking for, but I’ll bring your attention to it anyway.  I’ll start with links to resources:

1) As I mentioned, I don’t think this is what you were asking for (raw data on geographical area by municipality or population density), but it was the best thing that I could find: http://www.cedib.org/wp-content/uploads/2012/05/Mapa-2-Datos-demograficos.pdf.  Whoever put it together must have had to input raw data.  The sources cited are Wikipedia and INE, but I’ve been to both and was not able to find raw data broken out by municipality.  I suppose you could contact the person who put it together to see what raw data was used and from which sources and where within those sources.

2) You’ve probably been here: http://datos.ine.gob.bo/binbol/RpWebEngine.exe/Portal?BASE=CPV2012COM&lang=ESP.  While it is one of the nicer databases, I don’t think it will yield what you’re looking for and from the sounds of it, you’ve already been here, but if not, you may find the link useful.

3) The link here: http://censosbolivia.ine.gob.bo/sites/default/files/imagenes/fotos_galeria/ecc.jpg  does not provide what you’re looking for either, but it is a map that actually labels all of the municipalities, which may be helpful.

I did a cursory search of the Latin American Electronic Data Archive (LAEDA), but a lot of what I found for Bolivia seemed centered on elections, and the data doesn't appear to be all that recent.  Nevertheless, it might provide you with some good leads.  You can link to that search here: https://repositories.lib.utexas.edu/handle/2152/16309/statistics-by-country?countryCode=BO&nbitems=20&collection=4::92&simplefilter=1 year&time_filter_start_date=05/11/2014&time_filter_end_date=05/11/2015.  If nothing else, you would think that those involved with activities of an electoral nature would be able to provide data on its jurisdictions/municipalities.

Somebody suggested "Atlas Estadístico de Municipios," which I thought sounded promising, so I tried looking for a copy myself, but links I found by that name merely led me to population data.

Something that may be more obvious than most is the "National Institute of Statistics of Bolivia."  It is actually an account on ResearchGate.  With 2 members and 8 publications, I don't know how much it could help you, but it's worth a try.  You can link to it here: https://www.researchgate.net/institution/National_Insititute_of_Statistics_of_Bolivia.

I've also put out a query to a reference librarian who specializes in Latin America.  She did a really good job for me once before but due to the high tempo of the grad school program I was in, I couldn't put it all to good use.  I am hoping that if she finds some good resources that you will be able to do so.  If she does, I will let you know. 

Do you have a deadline by which you need to have this information?

One additional note: According to a Wikipedia article (citing Jorge Castel, "10 nuevos municipios elegirán a sus autoridades en los comicios," La Razón, 29 Marzo 2010), “New municipalities must have at least 10,000 residents, or 5,000 in the case of border areas.”  I don’t know if older municipalities have such restrictions.  You mentioned that some have as few as 509, so I would presume that older municipalities were not restricted by number.  Regardless, that doesn’t tell you anything about geographical size or population density of a municipality.

Thanks, Lisa. Yes, I'm familiar w/ most of those. One of the things I'm doing now is compiling a full municipal level dataset of socioeconomic and political data going back to the 1980s. I just found it odd that surface area (basic geography) wasn't readily available. 

I, too, find it odd that surface area isn't easily available, but, then again, living here in the U.S., I may be a bit spoiled by easy access to a sundry assortment of data that isn't as easily obtained in other parts of the world.  Still, doesn't the Google Duck go to Bolivia?  I guess the markers for municipalities may not be that easy for it to see. 

By the way, my research librarian contact did get back to me.  She directed me to some publications that I scrolled through, but it does not appear that population data is broken down by municipality or by surface area.  One of the links, however, was this new tool that I have not heard of or experimented with before.  It is called LandScan Documentation (http://web.ornl.gov/sci/landscan/landscan_documentation.shtml).  You have to request access just for a trial use of it.  Not having a solid need to do so (other than curiosity), I didn't bother requesting a trial account, but if you're interested, you can link to the request form here: http://online.eastview.com/freetrial/index.jsp.  If you do wind up using it and wouldn't mind sending me a message or posting something here to let me know how it works for you, I'd appreciate it.  Who knows, perhaps it could come in handy for a project down the road.

Here's another thing you could try, if you have the patience for it.  I know there are maps that break down each of the municipalities.  (In fact, I sent you a link to one.)  I also know some mapping tools will allow you to draw your own polygons and free form shapes onto the map interface.  Google Maps is one of these.  I'm sure you're wondering how that helps.  Well, when you draw a polygon/free form shape onto Google Maps, it gives you the area of the shape you've drawn.  I would suspect that there may be even more sophisticated map manipulation tools out there, especially if you're willing to pay a little money for them.  In the meantime, I've attached an example of what Google Maps can do for you (using provinces instead of municipalities just to make it easier for me).  It is definitely not an exact science and would be rather time consuming, especially once you get to those departments with all those tiny municipalities, but if I really wanted the data and there was no other source for it, I would use it as a last resort (and maybe even find an interested research assistant with a very meticulous hand).  I'd probably try to contact election officials first, though.  Either way, good luck to you.  I hope your project turns out better than expected.

Thanks, Lisa. I have some idea of how to "get" the data. But I need reputable, reliable, and valid data source that I can cite for my data analysis.

Yes, I already got it about a week ago from someone who answered earlier. Once I clean it up and add it to my dataset, I'll post it to my Harvard Dataverse repository.

I asked to the source that has shared to us this information (the Chief of Limits of the La Paz Municipality), authority that naturally has access to the updated data base from the Ministerio de Autonomías on this subject, and he told me that the shared data base for Miguel is public, even if it hasn't been published yet on the net.The ministery of autonomías (at least like a point of departure) requires to have this kind of data beacause of the following regulation and associated laws:

http://www.lexivox.org/norms/BO-DS-N1560.xhtml

At the same time, the (not resolved) existent conflicts of intermunicipal limits, are independent on regard to the objective of evaluating by example the "populatión density of voters" associated to a set of municipal polygons given anyway and necessarily used, case by case, on previous municipal elections. (This is in the same way that this factor, doesn't affect the results or interpretation from the last Census, equally associated to a sanctioned set of polygons, that enables to graphicate official maps of the data distribution for an specific date, by example 2012, regardless of those conflicts). 

Further criticism on regard to that data base (its limits and possibilities for scientific purposes), corresponds to be done by Miguel for the instance.

From my part I salute you all respectfully.

Best regards,

Hugo