Every year since 2000, The Zweig Letter has recognized the fastest-growing architecture, engineering, and environmental consulting firms on the basis of percentage growth and dollar growth. Over the years, the "Hot Firm" designation has become synonymous with success in the industry.

The Zweig Letter Hot Firm List of the 200 fastest-growing firms for 2009 appears below. The winning firms were honored at a special award ceremony during The Zweig Letter Hot Firm 2009 Conference, October 28-30, 2009 in Las Vegas.  The ranking by size and by type of work was also acknowledged at the conference.

1. Hill International, Inc. (Marlton, NJ)
2. Stantec Consulting Inc. (Irvine, CA)
3. WSP Group (USA) (New York, NY)
4. URS Corporation (San Francisco, CA)
5. Natural Resource Group, LLC (Minneapolis, MN)
6. Trow Global Inc (Brampton, ON)
7. Woodward Design+Build (New Orleans, LA)
8. RW Armstrong & Associates (Indianapolis, IN)
9. Hargrove and Associates, Inc. (Mobile, AL)
10. X-nth (Maitland, FL)
11. Perkins+Will (Chicago, IL)
12. ARCADIS (Highland Ranch, CO)
13. Cubellis (Boston, MA)
14. TolTest, Inc. (Maumee, OH)
15. ENGlobal Corporation (Houston, TX)
16. gkkworks (Irvine, CA)
17. AK Environmental, LLC (West Trenton, NJ)
18. Sovereign Consulting Inc. (Robbinsville, NJ)
19. Vector Engineering, Inc. (Grass Valley, CA)
20. Structural Integrity Associates, Inc. (San Jose, CA)
21. HDR (Omaha, NE)
22. Golder Associates (Mississauga, ON)
23. River Consulting (Columbus, OH)
24. Stress Engineering Services Inc. (Houston, TX)
25. SSOE, Inc. (Toledo, OH)
26. DOWL HKM (Anchorage, AK)
27. Paul C. Rizzo Associates, Inc. (Monroeville, PA)
28. SHW Group (Plano, TX)
29. Watermark (Lowell, MA)
30. Riverside Technology, Inc. (Fort Collins, CO)
31. Francis Cauffman (Philadelphia, PA)
32. EMR Inc. (Lawrence, KS)
33. Callison (Seattle, WA)
34. EN Engineering, LLC (Woodridge, IL)
35. Allana Buick & Bers, Inc. (Palo Alto, CA)
36. SB Architects (San Francisco, CA)
37. CHA (Albany, NY)
38. McDonough Bolyard Peck, Inc. (Fairfax, VA)
39. T Baker Smith, Inc. (Houma, LA)
40. TEC Inc. (Charlottesville, VA)
41. Tetra Tech (Pasadena, CA)
42. E M C Engineers, Inc. (Lakewood, CO)
43. NELSON (Philadelphia, PA)
44. Perkins Eastman (New York, NY)
45. JBA Consulting Engineers (Las Vegas, NV)
46. KJWW Engineering Consultants (Rock Island, IL)
47. Simpson Gumpertz & Heger Inc. (Waltham, MA)
48. Pond & Company (Norcross, GA)
49. Treanor Architects (Lawrence, KS)
50. Corgan Associates, Inc. (Dallas, TX)
51. Wight & Company (Darien, IL)
52. R.W. Beck, Inc. (Seattle, WA)
53. ENVIRON Holdings Inc. (Arlington, VA)
54. DLR Group (Omaha, NE)
55. Anshen & Allen, Architects, Inc. (San Francisco, CA)
56. Clark Nexsen (Norfolk, VA)
57. DLT&V Systems Engineering (Phoenix, AZ)
58. TEAM Integrated Engineering Inc. (San Antonio, TX)
59. Halcrow North America (New York, NY)
60. Schnabel Engineering, Inc. (Glen Allen, VA)
61. Apex Companies, LLC (Rockville, MD)
62. Vanderweil Engineers (Boston, MA)
63. GATE, LLC (Houston, TX)
64. EDSA, Inc. (Fort Lauderdale, FL)
65. Smolen Emr & Associates Architects, Inc (Rockville, MD)
66. Ghafari Associates, L.L.C. (Dearborn, MI)
67. Smith Seckman Reid, Inc. (Nashville, TN)
68. Kirksey (Houston, TX)
69. Terracon Consultants, Inc. (Olathe, KS)
70. Van Boerum & Frank Associates, Inc. (Salt Lake City, UT)
71. Luchs Consulting Engineers, LLC. (Meriden, CT)
72. Parametrix (Auburn, WA)
73. MTE Consultants Inc. (Kitchener, ON)
74. Testengeer Inc. (Port Lavaca, TX)
75. CirclePoint (San Francisco, CA)
76. Photo Science (Lexington, KY)
77. BKF Engineers (Redwood City, CA)
78. Trihydro Corporation (Laramie, WY)
79. HNTB Cos. (Kansas City, MI)
80. Coler & Colantonio, Inc. (Norwell, MA)
81. Aquaterra Environmental Solutions, Inc. (Overland Park, KS)
82. Nelson Nygaard Consulting Associates (San Francisco, CA)
83. Huckabee (Fort Worth, TX)
84. Foss Architecture & Interiors, Inc. (Fargo, ND)
85. RJ O’Connell & Associates, Inc (Stoneham, MA)
86. Wiser Company (Murfreesboro, TN)
87. Tsoi Kobus & Associates (Cambridge, MA)
88. KSA Engineers, Inc. (Longview, TX)
89. SCS Engineers (Long Beach, CA)
90. Pennoni Associates Inc. (Philadelphia, PA)
91. Gafcon, Inc. (San Diego, CA)
92. Enermodal Engineering (Kitchener, ON)
93. GUNDA CORPORATION, INC. (Houston, TX)
94. Group2 Architecture Engineering Ltd. (Red Deer, AB)
95. CB Engineers (San Francisco, CA)
96. King & King, Architects LLP (Syracuse, NY)
97. FXFOWLE Architects (New York, NY)
98. Kimley-Horn and Associates, Inc. (Raleigh, NC)
99. Marstel-Day, LLC (Fredericksburg, VA)
100. GEI Consultants Inc. (Woburn, MA)
101. Bergmann Associates (Rochester, NY)
102. Baldridge & Associates Structural Engineering, Inc. (Honolulu, HI)
103. ESI Consultants, Ltd (Naperville, IL)
104. Vanasse Hangen Brustlin, Inc. (Watertown, MA)
105. Brandow & Johnston, Inc. (Los Angeles, CA)
106. Groundwater & Environmental Services Inc. (Neptune, NJ)
107. Cherokee Enterprises, Inc. (Miami Lakes, FL)
108. KCI Technologies Inc. (Sparks, MD)
109. EAPC (Grand Forks, ND)
110. Crafton Tull Sparks (Rogers, AK)
111. ERRG (Martinez, CA)
112. Horizon Engineering Associates, LLC (New York, NY)
113. JRS Architect, P.C. (Mineola, NY)
114. Interstates Engineering, Inc. (Sioux Center, IA)
115. Process Plus, LLC (Cincinnati, OH)
116. McKim & Creed (Raleigh, NC)
117. Berger Devine Yaeger, Inc. (Kansas City, MO)
118. Perez & Perez Architects Planners (Miami, FL)
119. Weaver Boos Consultants (Chicago, IL)
120. Environmental Resolutions, Inc. (Lake Forest, CA)
121. Primera Engineers (Chicago, IL)
122. Moody Nolan, Inc. (Columbus, OH)
123. Fentress Architects (Denver, CO)
124. Arora Engineers, Inc. (Chadds Ford, PA)
125. Fehr-Graham & Associates LLC (Freeport, IL)
126. Tectonic Engineering & Surveying Consultants P.C. (Mountainville, NY)
127. P.W. Grosser Consulting, Inc. (Bohemia, NY)
128. Woolpert (Dayton, OH)
129. Lowe Engineers LLC (Atlanta, GA)
130. HAKS Engineers, Architects and Land Surveyors, P.C. (New York, NY)
131. Baseline Engineering (Golden, CO)
132. H2Engineering Inc (Tallahassee, FL)
133. Collins Engineers, Inc. (Chicago, IL)
134. M/E Engineering PC (Rochester, NY)
135. Dvirka And Bartilucci Consulting Engineers (Long Island, NY)
136. Harper Houf Peterson Righellis Inc. (Portland, OR)
137. Jacobs Associates (San Francisco, CA)
138. Woodard & Curran (Portland, ME)
139. Mead & Hunt, Inc. (Madison, WI)
140. Potomac-Hudson Engineering, Inc. (Bethesda, MD)
141. McGill Associates, PA (Asheville, NC)
142. BJAC pa (Raleigh, NC)
143. Ruby+Associates, Inc. (Farmington Hills, MI)
144. GARY GUY WILSON, AIA, PC (Las Vegas, NV)
145. V3 Companies Ltd (Woodridge, IL)
146. Walker Partners (formerly known as G. E.Walker & Associates, L.L.C.) (Waco, TX)
147. BLRB Architects, p.s. (Tacoma, WA)
148. Langan Engineering and Environmental Services (Elmwood Park, NJ)
149. EM-Assist, Inc. (Folsom, CA)
150. Hood-Patterson & Dewar, Inc. (Norcross, GA)
151. PGAL (Houston, TX)
152. LS3P Associates, Ltd. (Charleston, SC)
153. Hipp Engineering & Consulting, Inc. (Raleigh, NC)
154. H2M Group (Melville, NY)
155. DCI Engineers (Bellevue, WA)
156. CMX Inc (Manalapan, NJ)
157. RAND Engineering & Architecture, PC (New York, NY)
158. Finley Engineering Company, Inc. (Lamar, MO)
159. Hanson Professional Services Incorporated (Springfield, IL)
160. Barton & Loguidice, P.C. (Syracuse, NY)
161. Sam Schwartz Engineering (New York, NY)
162. Merrick & Company (Aurora, CO)
163. Degenkolb Engineers (San Francisco, CA)
164. Dekker/Perich/Sabatini (Albuquerque, NM)
165. Farnsworth Group, Inc. (Bloomington, IL)
166. Ulteig Engineers, Inc. (Fargo, ND)
167. Caruana & Associates (Long Beach, CA)
168. Harrison French & Associates, LTD (Bentonville, AR)
169. Dagher Engineering (New York, NY)
170. Lochner (Chicago, IL)
171. Birdsall Services Group, Inc. (Sea Girt, NJ)
172. Jaster-Quintanilla (Austin, TX)
173. PE-Services (Lebanon, OH)
174. Sparling (Seattle, WA)
175. Cobb Engineering Company (Oklahoma City, OK)
176. Array Healthcare Facilities Solutions, Inc. (King of Prussia, PA)
177. RPA Associates Inc. (Wyomissing, PA)
178. Chen and Associates (Fort Lauderdale, FL)
179. Converse Consultants (Monrovia, CA)
180. Long Engineering, Inc. (Atlanta, GA)
181. Gilsanz Murray Steficek (New York, NY)
182. Dudek (Encinitas, CA)
183. Cuningham Group Architecture, P.A. (Minneapolis, MN)
184. YU & Associates, Inc. (Elmwood Park, NJ)
185. NAC|Architecture (Spokane, WA)
186. Perkowitz+Ruth Architects (Long Beach, CA)
187. ACAI Associates, Inc (Fort Lauderdale, FL)
188. BrightFields, Inc. (Wilmington, DL)
189. Core States Group (Atlanta, GA)
190. Daniel B. Stephens & Associates, Inc. (Albuquerque, NM)
191. Mabbett & Associates, Inc (Bedford, MA)
192. Calvin, Giordano & Associates, Inc. (Fort Lauderdale, FL)
193. JONES & CARTER, INC. (Houston, TX)
194. Wier & Associates, Inc. (Arlington, TX)
195. Passero Associates (Rochester, NY)
196. Sherlock, Smith and Adams, Inc. (Montgomery, AL)
197. CPH Engineers, Inc. (Sanford, FL)
198. Traffic Planning and Design, Inc. (Pottstown, PA)
199. ECOM Engineering, Inc. (Sacramento, CA)
200. GH2 Architects, LLC (Tulsa, OK)