| Subdivision Name | Code | Plat Vol | Plat Page | Document Number |
| O'CONNELL SUB | OCONL | 57 | 27 | |
| O'CONNOR HEIGHTS ADD | OCONRHT | 7 | 79 | |
| O'HARA'S RESUB | OHARA/ | 248 | A | 1778622 |
| O. DAVIDSON'S ADD | DVDSN O | 1 | 107 | |
| O. DAVIDSON'S HEIRS SUB | DVDSN OHS | 16 | 11 | |
| O. DAVIDSON'S SUB | DVDSN OS | 5 | 26 | |
| O.N. SHEDD'S SUB | SHD ON | 5 | 18 | |
| OAK AVENUE SUB | OAKAV | 640 | A | 91K50331 |
| OAK BLUFF | OAKBLF | 104 | A | 1534690 |
| OAK BLUFF RESUBDIVISION | OAKBLF/ | 264 | A | 1797692 |
| OAK CREEK TOWNHOMES | OAKCKT | | | 2005K131768 |
| OAK CREEK TOWNHOMES UNIT 2R | OAKCKT2R | | | 2008K075741 |
| OAK CREEK-WEST TOWNHOME | OAKCKWT | 74 | *28 | |
| OAK CREEK-WEST TOWNHOME | OAKCKWT 3 | 74 | *53 | |
| OAK CREEK-WEST TOWNHOME | OAKCKWT 4 | 70 | *10 | |
| OAK CREEK-WEST TOWNHOME | OAKCKWT 5 | 76 | *22 | |
| OAK CREEK-WEST TOWNHOME | OAKCKWT 6 | 76 | *61 | |
| OAK CREEK-WEST TOWNHOME | OAKCKWT A | 74 | *36 | |
| OAK CREST UNIT 1 | OAKCREST1 | A199 | B | 98K097201 |
| OAK CREST UNIT 2 | OAKCREST2 | A296 | B | 1999K082523 |
| OAK FOREST SUB, UNIT A, | OAKFRT A | 42 | 39 | |
| OAK FOREST, UNIT B | OAKFRT B | 55 | 7 | |
| OAK FOREST, UNIT C | OAKFRT C | 55 | 43 | |
| OAK GLEN SUB | OAKGLN | *638 | *A&B | 91K49918 |
| OAK GROVE ESTATES | OAKGRVET | 66 | *21 | |
| OAK GROVE SUB | OAKGR | 619 | B | 91K37571 |
| OAK HILL OF N AURORA | OAKHLOFN1 | A75 | A&B | 97K012218 |
| OAK HILL OF N AURORA | OAKHLOFN2 | A121 | A&B | 97K076956 |
| OAK HILL SUB | OAKHLS | 37 | 33 | |
| OAK HILL SUB UNIT 1 | OAKHLNA | 54 | 17 | |
| OAK KNOLLS ESTATE | OAKKNET 1 | 40 | 2 | |
| OAK KNOLLS ESTATES | OAKKNET 2 | 41 | 36 | |
| OAK KNOLLS JUNIOR | OAKKNJ | 56 | 5 | |
| OAK MANOR SUB | OAKMN | 33 | 48 | |
| OAK MEADOWS / LT 7-11 | OAKMD/7 | 745 | A | 93K07019 |
| OAK MEADOWS SUB | OAKMD | 539 | A | 90K21072 |
| OAK OPENINGS SUB, | OAKOPG 1 | 62 | 11 | |
| OAK OPENINGS SUB, | OAKOPG 2 | 66 | 43 | |
| OAK OPENINGS SUB, | OAKOPG 3 | 72 | 5 | |
| OAK PARK ADD | OAKPK | 10 | 18 | |
| OAK RIDGE | OAKRDG | 13 | 28 | |
| OAK RIDGE FARM SUB | OAKRDGF | *834 | *A&B | 94K021979 |
| OAK SHADOWS RESUBDIVISION | OAKSHDW/7 | | | 2005K118327 |
| OAK SHADOWS SUB | OAKSHDWS | A698 | A&B | 2003K021112 |
| OAK VIEW MANOR, UNIT 1 | OAKVWMN 1 | 36 | 40 | |
| OAKCREEK | OAKCK | 50 | 29 | |
| OAKCREST, UNIT 1 | OAKCRT 1 | 46 | 45 | |
| OAKCREST, UNIT 2 | OAKCRT 2 | 55 | 42 | |
| OAKHILL ACRES UNIT 1 | OAKHLAC 1 | 46 | 5 | |
| OAKHILLS | OAKHL | 26 | 42 | |
| OAKLAWN | OAKLN | 11 | 27 | |
| OAKMONT OF CAMPTON HILL | OAKMONT | A144 | A&B | 98K028471 |
| OAKRIDGE RESUBDIVISION | OAKRDGWD/ | A230 | B | 1999K019345 |
| OAKS CLUB, THE | OAKCB | *568 | *A&B | 90K48070 |
| OAKS OF ST. CHAS, FOX | OAKS SC | 71 | 13 | |
| OAKSHIRE ESTATES SUB | OAKSHET | 653 | A&B | 91K65068 |
| OAKTON TERRACE | OAKTNTR | 72 | 17 | |
| OAKVIEW ADD | OAKVW | 12 | 12 | |
| OAKVIEW CORPORATE PARK | OAKVWCPK | | | 2007K009757 |
| OAKVIEW CORPORATE PARK FIRST RESUB | OAKVWCPK/1 | | | 2008K011226 |
| OAKWOOD ADD | OAKWD | 5 | 75 | |
| OAKWOOD SUB | OAKWDS | 44 | 24 | |
| OATES RESUBDIVISION | OATES/ | | | 2008K021659 |
| OBERWEIS DAIRY SUB | OBRWSDRY | 891 | B | 95K001238 |
| OBERWEIS SUB, UNIT 1 | OBRWS 1 | 39 | 11 | |
| OBERWEIS SUB, UNIT 2 | OBRWS 2 | 39 | 49 | |
| OBERWEIS SUB, UNIT 3 | OBRWS 3 | 43 | 2 | |
| OBERWEIS SUB, UNIT 4 | OBRWS 4 | 43 | 30 | |
| OBERWEIS SUB, UNIT 5 | OBRWS 5 | 44 | 28 | |
| OBERWEIS SUB, UNIT 6 | OBRWS 6 | 49 | 5 | |
| OGBORN-MCCLURE SUB | OGBMC | 55 | 31 | |
| OGDEN GARDENS | OGDENGN | 26 | 1 | |
| OHIO TERRACE | OHIOTR | 54 | 39 | |
| OLD MILL MANOR TOWNHOME | OLDMMTH | 740 | A | 92K93037 |
| OLD MILL MANOR, UNIT 1 | OLDMLMN 1 | 522 | B | 90K13506 |
| OLD MILL MANOR, UNIT 2 | OLDMLMN 2 | 630 | B | 91K49267 |
| OLD MILL MANOR, UNIT 3 | OLDMLMN 3 | 690 | B | 92K39990 |
| OLD MILL MANOR, UNIT 4 | OLDMLMN 4 | 783 | B | 93K69266 |
| OLD MILL MANOR, UNIT 5 | OLDMLMN 5 | 804 | B | 93K90119 |
| OLD MILL MANOR, UNIT 6 | OLDMLMN 6 | 818 | A | 93K102054 |
| OLD MILL MANOR, UNIT 7 | OLDMLMN 7 | 850 | A | 94K047305 |
| OLD MILL MANOR, UNIT 8 | OLDMLMN 8 | 850 | B | 94K047308 |
| OLD MILL MANOR, UNIT 9 | OLDMLMN 9 | A54 | A&B | 96K076654 |
| OLD OAKS ESTATES SUB | OLDOKET | 364 | B | 1911589 |
| OLD OAKS SQUARE SUBDIVISION | OLDOKSQ | | | 2007K025860 |
| OLD WORLD RESUB | OLDWLD/ | *28 | A&B | 1473693 |
| OLD WORLD SUB | OLDWLD | 48 | 46 | |
| OLD WORLD TOWNHOUSE | OWTCOND | 52 | *55 | |
| OLIVE GARDENS RESUB | OLIVEGN/ | 809 | A | 93K095210 |
| OLIVER-HOFFMAN CHARLESTOWN DEVELOPMENT | OLHOFFCHASTN | | | 2009K095641 |
| OLIVER-HOFFMAN CHARLESTOWN DEVELOPMENT RESUB | OLHOFFCHSTN/ | | | 2010K046244 |
| OLSEN SUBDIVISION | OLSEN | A388 | B | 2000K047275 |
| OLYMPIC DRIVE RESUB | OLYMCD/ | 61 | 15 | |
| ON BRENTWOOD'S POND | ONBRTPD | *868 | *A&B | 94K075643 |
| ONE COMMERCE CENTER | ONECCC | 84 | 84 | |
| ORCHARD BAY TOWNHOMES | ORCDBYTH | 619 | A | 91K37075 |
| ORCHARD BUSINESS PARK | ORCDBPK | A688 | B* | 2002K166280 |
| ORCHARD COMMERCE CENTER | ORCDCCTR | | | 2005K110890 |
| ORCHARD COMMERCE CENTER-FIRST RESUB | ORCDCCTR/1 | | | 2007K060731 |
| ORCHARD COMMONS | ORCDC | | | 2007K081978 |
| ORCHARD CORRIDOR OFFICE PARK | ORCDCORR1 | | | 2006K088647 |
| ORCHARD CROSSING | ORCDCR | 830 | A&B | 94K015115 |
| ORCHARD CROSSING UNIT 1 | ORCDCRNA1 | A276 | A&B* | 1999K060136 |
| ORCHARD CROSSING UNIT 2 | ORCDCRNA2 | A310 | A&B | 1999K090879 |
| ORCHARD ESTATES UNIT 1 | ORCDET 1 | A301 | A&B | 1999K083918 |
| ORCHARD ESTATES UNIT 2 | ORCDET 2 | A349 | A&B | 1999K121497 |
| ORCHARD GATEWAY,UNIT 1 | ORCDGTW1/ | 1000 | B | 96K022584 |
| ORCHARD GATEWAY,UNIT 1 | ORCDGTW 1 | 922 | A | 95K025349 |
| ORCHARD GATEWAY,UNIT 1C | ORCDGTW1C | A63 | A&B | 96K082461 |
| ORCHARD GREEN SUB | ORCDGR 4 | 50 | 25 | |
| ORCHARD GREEN SUB | ORCDGR 1 | 45 | 43 | |
| ORCHARD GREEN SUB | ORCDGR 2 | 48 | 44 | |
| ORCHARD GREEN SUB | ORCDGR 3 | 50 | 23 | |
| ORCHARD GROVE SUB | ORCDGROVE | A696 | B | 2003K017928 |
| ORCHARD LAKE DEVELOPMENT UNIT 1 | ORCDLKD 1 | | | 2006K134918 |
| ORCHARD LAKE DEVELOPMENT UNIT 1A | ORCDLKD 1A | | | 2008K042152 |
| ORCHARD LAKE DEVELOPMENT UNIT 2 | ORCDLKD 2 | | | 2008K040026 |
| ORCHARD RD BUSINESS PK | ORCDRDBPK | A404 | A&B | 2000K057115 |
| ORCHARD ROAD INDUSTRIAL | ORCDRIPK | 397 | B | 1927258 |
| ORCHARD ROAD SUB | ORCDRD/5&6 | | | 2004K076846 |
| ORCHARD ROAD SUB | ORCDRD/3 | | | 2006K044909 |
| ORCHARD ROAD SUB | ORCDRD | A741 | A&B* | 2003K091879 |
| ORCHARD ROAD SUB | ORCDRD/1 | | | 2007K095124 |
| ORCHARD VALLEY OFFICE | ORCDVOPC2A | | | 2004K082558 |
| ORCHARD VALLEY OFFICE | ORCDVOPC1A | | | 2004K077278 |
| ORCHARD VALLEY OFFICE | ORCDVOPC2 | | | 2004K019541 |
| ORCHARD VALLEY OFFICE | ORCDVOPC | | | 2003K185931 |
| ORCHARD VALLEY UNIT 1 | ORCDVY 1 | *584 | *A&B | 90K62092 |
| ORCHARD VALLEY UNIT 2 | ORCDVY 2 | 602 | A&B | 91K18533 |
| ORCHARD VALLEY UNIT 3 | ORCDVY 3 | *597 | *A&B | 91K13306 |
| ORCHARD VALLEY UNIT 4 | ORCDVY 4 | A42 | A&B | 96K066777 |
| ORCHARD VALLEY UNIT 5 | ORCDVY 5 | 603 | A&B | 91K18534 |
| ORCHARD VALLEY UNIT 6 | ORCDVY 6 | *604 | *A&B | 91K18535 |
| ORCHARD VALLEY UNIT 7 | ORCDVY 7 | *624 | *B | 91K40127 |
| ORCHARD VALLEY VILLAGE | ORCDVVC 8 | *982 | *B | 95K076445 |
| ORCHARD VALLEY VILLAGE | ORCDVVC 9 | *985 | *A&B | 95K076447 |
| ORCHARD VILLAGE | ORCDVG | A249 | A&B | 1999K031534 |
| OTIS SUB | OTIS | 1 | 108 | |
| OTTER CREEK SUB | OTTRCK | 48 | 10 | |
| OURY DIVISION | OURYD | 819 | A | 93K102425 |
| OUTHOUSE'S ADD | OUTHOS | 14 | 12 | |
| OVE DIVISION | OVE | 679 | A | 92K22587 |
| OWNER RESUB OF GENEVA | OWNR/GV | 43 | 49 | |
| OWNER' RESUB OF | OWNR/PL | 26 | 50 | |
| OWNER'S PLAT | OWNR K | 29 | 5 | |
| OWNER'S PLAT OF | OWNR S | 30 | 17 | |
| OWNER'S PLAT OF | OWNR D | 28 | 9 | |
| OWNER'S PLAT OF 15-38-8 | OWNP A | 44 | 35 | |
| OWNER'S PLAT,N. AURORA | OWNR NA | 32 | 48 | |
| OWNER'S RESUB | OWNR/A | 28 | 28 | |
| OWNER'S RESUB | OWNR/RS | 67 | 19 | |
| OWNER'S RESUB OF | OWNR/GR | 31 | 4 | |
| OWNER'S SUB | OWNRS | 21 | 48 | |
| OWNER'S SUB OF EDWARD'S | OWNR ED | 43 | 34 | |
| OWNER'S SUB OF ELMWOOD | OWNR EL | 36 | 32 | |
| OWNER'S SUB OF LT 1 OF | OWNR TC | 46 | 6 | |
| OWNER'S SUB,N. AURORA | OWNER NAS | 31 | 44 | |
| OWNER'S/ OF TYLER BLUFF | TYLRBFO/ | 72 | *29 | |
| OWNERS PLAT | OWNR J | 27 | 47 | |
| OWNERS PLAT OF LOT 24 | OWNR W2 | 44 | 42 | |
| OWNERS PLAT OF SUB | OWNR 39 | 43 | B | 1481559 |
| OWNERS PLAT OF WEBER | OWNR W | 41 | 1 | |
| OWNERS PLAT, GEORGE E. | OWNR L | 44 | 31 | |
| OWNERS SUB, MALLARD | OWNRMLN | 55 | *46 | |
| OWNERS' 1ST RESUB OF | OWNR FR | 1221 | 415 | |
| OWNERS' SUB OF | OWNR H&B | 34 | 44 | |
