PLEASE add to this because I know more exist but, this is a long list. AND I do not have all the info for everything so if you do, please share. This is very long though, so bear with me. BUT for any venue that allows outside catering, I highly recommend KS Catering for their quality but incredibly affordability.
I got bored since my fiance is working mandatory 12 hour days as a result of the big storm sooo I came up with something useful. The rest is copy paste, ENJOY!
BY COUNTY
** indicates no detailed information
ANNE ARUNDEL COUNTY
Camp Letts, Edgewater MD - Also more nautical with a rustic style room, holds 200. Must use camp Chef - no clue on pricing or other details.
http://meganbeth.com/blog/2009/06/18/meghan-and-bill/BALTIMORE COUNTY
Richardson Farms, Glen Arm MD - holds over 200 - All inclusive, starts in the $70s per person before alcohol (and still tax and gratuity needs to be added). And I am highly jealous of anyone who can afford it, its my dream venue, I live basically across the street and used to ride my dirtbike here lol. Hard to find pictures but I live there, it is really pretty. No real website, you need to contact them and ask for catering for the Barn in Glen Arm. 410-335-5900.
**Camp Frettard, Reisterstown MD - (Weinberg Center, but be sure it's the one at Camp Frettard)
CALVERT COUNTY
Jefferson Patterson Park, St. Leonard MD - Hugely affordable - Holds 168 but can add more seating - well under $1000 - I think it allows outside catering - be sure to read the rules, it is a park so there are likely time limits and noise rules.
http://www.jefpat.org/Documents/2012-RentalFlier-web.pdf and
http://www.jefpat.org/rentals.htmlCARROLL COUNTY
Union Mills Homestead, Westminster MD - (my venue) Holds about 140 in the barn, but can extend into adjacent tent and hold up to 210 - Kountry Kafe is the sole caterer (starts around $34pp) Rental $700, Already decorated, get for entire weekend. Google "union mills homestead wedding Ewing" to see pictures.
http://www.unionmills.org/
CECIL COUNTYThe Tea Barn, Elkton MD - Holds 125, VERY inexpensive (less than $1000) - Allows outside catering (this is a good bargain with the right catering)
http://www.ccgov.org/tourism/search/conferences.cfm Scroll to Elkton
Elk Manor Farm, North East MD - More nautical than rustic but there is a barn-like room. For those who want waterfront its very pretty. Not clear on how many people, website says 400 but for the grounds, not the "barn". No pricing.
http://www.weddingwire.com/reviews/elk-manor-farms-north-east/86342ac51e39569a.html and
http://www.elkmanor.com/**Spring Hill Manor, Rising Sun MD - Gorgeous wedding here.
http://laurenfair.wordpress.com/2011/11/28/courtney-lewis-spring-hill-manor-vintage-barn-wedding-photography-rising-sun-maryland-wedding-photographer/ and
http://www.springhillmanor.com/default.htmlFREDERICK COUNTY
Mathwig Estate Event Barn, Thurmont MD - Holds 150 comfortably. Get entire weekend and several rentals, no A/C. A knottie said prices were reasonable but have no solid numbers. Looks like you can have outside catering.
http://www.lawyersmoonlightmaze.com/Welcome/Event_Barn.htmlThe Barn at Serra Valley, Mt. Airy MD - Very new, holds 140. Appears to include really cool furniture too. Seems very decked out. No clue on pricing but seems to allow outside catering.
http://serravalleyfarms.com/Serravalley_Farms/Function_Center.html**Ostertag Vistas, Myersville MD - Holds 200 but its all separated. Freaking Gorgeous.
http://www.frederick.com/ostertag_vistas-sp-4685/**Linganore Winecellars, Frederick MD - Holds 150 - seems to have limited time, very pretty.
http://www.linganorewines.com/facilityrental.htmlGARRETT COUNTY
**Chanteclair Farm, Deep Creek MD - http://www.chanteclairefarm.com/HARFORD COUNTY
Grimmel Farms, Jarrettsville MD - Huge, probably holds well over 200. Quoted $3K to rent but no bathrooms (need to get a bathroom trailer or something) - Outside catering allowed. Need to call and ask for Kristen's number, 443-807-9735 <--- number for farm.
Rockfield Manor, Bel Air MD - Holds 125 (ceremony only, reception is tented) - $1200-1800, unsure if it includes tent. Also unsure about rental time or if they allow outside catering.
http://www.rockfieldmanor.com/weddings.htmlGeneva Farms, Street MD - Holds around 200. Roughtly $50-60 per person for everything (on-site catering) outside is more barn-like, the inside is a little less rustic. Owners are extremely friendly and helpful.
http://harfordcaterers.com/HOWARD COUNTY
Howard County Conservatory, Woodstock MD - Max 130-140 people. $2200 for Saturday plus another $250 to use the barn for ceremony. Indoor space is also pretty, sort of modern styled rustic with beautiful windows, A/C.
http://www.hcconservancy.org/gudelsky-center-rental-facilities.htmlNixon's Farm, West Friendship MD - 50 person minimum. Starts at $28 per person. Doesn't include other fees. Seems to book up quickly. Recommends booking 5 months - 2 years in advance.
http://www.nixonsfarm.com/wedding.htmKENT COUNTY
Inn at Huntingfield Creek, Rock Hall MD - 2100 sq. ft. not a huge guest accommodation.
http://www.huntingfield.com/special-events/MONTGOMERY COUNTY
Rockland Farm Barn, Poolesville MD - Holds 150, 8 hour window. $2000-2500 for rental, no clue if they have a preferred vendor list.
http://www.rocklandsfarmmd.com/Barn.html and
http://sweetteaphotographybylisamarie.blogspot.com/2011/09/leslie-seans-maryland-farm-wedding.htmlThe Lodge at Seneca Creek, Boyds MD - $1600-2200 for rental, allows outside catering, holds 120 inside, can hold up to 300 outside. Don't think tents are provided. Unsure on time limit.
http://www.uniquevenues.com/LodgeSenecaCreekSmokey Glen Farm, Gaithersburg MD - has 5 areas for events, one is barn. Catering onsite, ranges from $30-$70 per person. Barn prices range from $500-$1500 for rental depending on time of year.
http://smokeyglenfarm.com/ Click on Download our Brochure for pricing. Pics:
http://www.unitedwithlove.com/2011/04/04/rustic-vintage-inspired-marylan-farm-summer-wedding/**Linden Farm, Dickerson MD - http://home.comcast.net/~sugarloafcitizens/gothicbarn.htmlST. MARY'S COUNTY
Flora Corn Farm, Mechanicsville MD - Holds 125, starts at $3000.
PENNSYLVANIA
**Duke Farms, Farm Grove PA - $1900 for just site.
http://www.thedukefarm.com/rentalpol_facility.html