The Louisiana Constitution of 1845 allowed the legislature to establish "as many district courts as the public interest may require" (Title IV, Article 75). These district courts were to have original jurisdiction in all civil cases, when the amount in dispute exceeded $50, exclusive of interest. Act 43 of 1846 further detailed the organization of the district courts in the parish and city of New Orleans. The Act provided for five District Courts: the First, Second, Third, Fourth, and Fifth District Courts of New Orleans.

The Third District court was to keep two dockets, a "Preference Docket" and an "Ordinary Docket." On the Preference Docket were to be placed "all cases of appeal from Justices of the Peace" and these cases were to be tried "by preference over all cases found on the Ordinary or other dockets." The Judge of the court decided "summarily and without argument" which docket a case was to be assigned. The Act stipulated that all appeal cases "shall be de novo, and shall be conducted according to the rules and regulations provided by law for the trial of appeals from the judgments of the Associate Judges of the City Courts of New Orleans." Any party introducing new evidence into the appeal was to pay the costs of the appeal.

Cases pending before the Judge of the City Court and those pending before the Parish Court (both defunct by 1846) were also to be transferred to Third District Court.

Act 229 of 1853 further organized the Orleans Parish courts, giving exclusive jurisdiction over certain types of cases to the courts (criminal matters to First District Court, probate matters to Second District Court, for example) and added a new court, the Sixth District Court, to have jurisdiction over cases pending in the City of Lafayette, newly incorporated into Orleans Parish from Jefferson Parish. The remaining courts (Third, Fourth, and Fifth District Courts) were to have "concurrent jurisdiction of all civil cases whatever" that did not fall under the jurisdiction of the special courts.

Prior to this 1853 Act, the Third District Court (along with the other numbered district courts) also handled matters that were not purely commercial in nature, including successions. An index to the successions before the Third District Court (and other courts) can be found online here: archives.nolalibrary.org/inv/succes1.htm. Most of these records are available on microfilm.

The Consitution of 1868 retained and reinstituted the six numbered district courts in Orleans Parish and added a seventh court. It reiterated the exclusive jurisdiction of several of the courts (First District Court, exclusive criminal jurisdiction; Second District Court, exclusive probate jurisdiction; Third District Court, exclusive jurisdiction of appeals from justices of the peace). Fourth, Fifth, Sixth, and Seventh District Courts were given exclusive jurisdiction in all civil cases, except probate, when the sum in contest was above one hundred dollars, exclusive of interest. In most courts, the docket numbering begins again at this time, with a second series of records.

Act 7 of 1868 ordered that all cases pending in the Third District Court, exclusive of appeals from the justices of the peace, be transfered to the newly created Seventh District Court (which ceased operation in 1872, replaced by the Superior District Court.)

The consititution of 1879 consolidated all of the remaining civil ourts into a single court, Civil District Court, still in existence today. Cases pending in Third District Court were transferred to this new court under new docket numbers.