EPSG:4267

BOUNDCRS[
    SOURCECRS[
        GEOGCRS["NAD27",
            DATUM["North American Datum 1927",
                ELLIPSOID["Clarke 1866",6378206.4,294.978698213898,
                    LENGTHUNIT["metre",1]]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            CS[ellipsoidal,2],
                AXIS["geodetic latitude (Lat)",north,
                    ORDER[1],
                    ANGLEUNIT["degree",0.0174532925199433]],
                AXIS["geodetic longitude (Lon)",east,
                    ORDER[2],
                    ANGLEUNIT["degree",0.0174532925199433]],
            USAGE[
                SCOPE["Geodesy."],
                AREA["North and central America: Antigua and Barbuda - onshore. Bahamas - onshore plus offshore over internal continental shelf only. Belize - onshore. British Virgin Islands - onshore. Canada onshore - Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, Nunavut, Ontario, Prince Edward Island, Quebec, Saskatchewan and Yukon - plus offshore east coast. Cuba - onshore and offshore. El Salvador - onshore. Guatemala - onshore. Honduras - onshore. Panama - onshore. Puerto Rico - onshore. Mexico - onshore plus offshore east coast. Nicaragua - onshore. United States (USA) onshore and offshore - Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin and Wyoming - plus offshore . US Virgin Islands - onshore."],
                BBOX[7.15,167.65,83.17,-47.74]],
            ID["EPSG",4267]]],
    TARGETCRS[
        GEOGCRS["NAD83",
            DATUM["North American Datum 1983",
                ELLIPSOID["GRS 1980",6378137,298.257222101,
                    LENGTHUNIT["metre",1]]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            CS[ellipsoidal,2],
                AXIS["geodetic latitude (Lat)",north,
                    ORDER[1],
                    ANGLEUNIT["degree",0.0174532925199433]],
                AXIS["geodetic longitude (Lon)",east,
                    ORDER[2],
                    ANGLEUNIT["degree",0.0174532925199433]],
            USAGE[
                SCOPE["Geodesy."],
                AREA["North America - onshore and offshore: Canada - Alberta; British Columbia; Manitoba; New Brunswick; Newfoundland and Labrador; Northwest Territories; Nova Scotia; Nunavut; Ontario; Prince Edward Island; Quebec; Saskatchewan; Yukon. Puerto Rico. United States (USA) - Alabama; Alaska; Arizona; Arkansas; California; Colorado; Connecticut; Delaware; Florida; Georgia; Hawaii; Idaho; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; Mississippi; Missouri; Montana; Nebraska; Nevada; New Hampshire; New Jersey; New Mexico; New York; North Carolina; North Dakota; Ohio; Oklahoma; Oregon; Pennsylvania; Rhode Island; South Carolina; South Dakota; Tennessee; Texas; Utah; Vermont; Virginia; Washington; West Virginia; Wisconsin; Wyoming. US Virgin Islands. British Virgin Islands."],
                BBOX[14.92,167.65,86.45,-40.73]],
            ID["EPSG",4269]]],
    ABRIDGEDTRANSFORMATION["NAD27 to NAD83 (8)",
        METHOD["NADCON5 (2D)",
            ID["EPSG",1074]],
        PARAMETERFILE["Latitude difference file","nadcon5.nad27.nad83_1986.alaska.lat.trn.20160901.b"],
        PARAMETERFILE["Longitude difference file","nadcon5.nad27.nad83_1986.alaska.lon.trn.20160901.b"],
        USAGE[
            SCOPE["Geodesy."],
            AREA["United States (USA) - Alaska."],
            BBOX[51.3,172.42,71.4,-129.99]],
        ID["EPSG",8549],
        REMARK["Uses NADCON5 method which expects longitudes positive east in range 0-360°; source and target CRSs have longitudes positive east in range -180° to +180°. Accuracy at 67% confidence level is 0.5m onshore, 5m nearshore and undetermined farther offshore."]]]

proj4.defs("EPSG:4267","+proj=longlat +datum=NAD27 +no_defs +type=crs");

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "BoundCRS",
    "source_crs": {
        "type": "GeographicCRS",
        "name": "NAD27",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "North American Datum 1927",
            "ellipsoid": {
                "name": "Clarke 1866",
                "semi_major_axis": 6378206.4,
                "semi_minor_axis": 6356583.8
            }
        },
        "coordinate_system": {
            "subtype": "ellipsoidal",
            "axis": [
                {
                    "name": "Geodetic latitude",
                    "abbreviation": "Lat",
                    "direction": "north",
                    "unit": "degree"
                },
                {
                    "name": "Geodetic longitude",
                    "abbreviation": "Lon",
                    "direction": "east",
                    "unit": "degree"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 4267
        }
    },
    "target_crs": {
        "type": "GeographicCRS",
        "name": "NAD83",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "North American Datum 1983",
            "ellipsoid": {
                "name": "GRS 1980",
                "semi_major_axis": 6378137,
                "inverse_flattening": 298.257222101
            }
        },
        "coordinate_system": {
            "subtype": "ellipsoidal",
            "axis": [
                {
                    "name": "Geodetic latitude",
                    "abbreviation": "Lat",
                    "direction": "north",
                    "unit": "degree"
                },
                {
                    "name": "Geodetic longitude",
                    "abbreviation": "Lon",
                    "direction": "east",
                    "unit": "degree"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 4269
        }
    },
    "transformation": {
        "name": "NAD27 to NAD83 (8)",
        "method": {
            "name": "NADCON5 (2D)",
            "id": {
                "authority": "EPSG",
                "code": 1074
            }
        },
        "parameters": [
            {
                "name": "Latitude difference file",
                "value": "nadcon5.nad27.nad83_1986.alaska.lat.trn.20160901.b",
                "id": {
                    "authority": "EPSG",
                    "code": 8657
                }
            },
            {
                "name": "Longitude difference file",
                "value": "nadcon5.nad27.nad83_1986.alaska.lon.trn.20160901.b",
                "id": {
                    "authority": "EPSG",
                    "code": 8658
                }
            }
        ],
        "id": {
            "authority": "EPSG",
            "code": 8549
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=longlat +datum=NAD27 +no_defs +type=crs">
	<Layer srs="+proj=longlat +datum=NAD27 +no_defs +type=crs">
	</Layer>
</Map>