Reading Large TXT Files Throws System Out of Memory Exception

static readonly Regex ParseLineRegex = new Regex(@"^(?<ip>\S*) - - \[(?<date>.*)\] (?<method>\S+) (?<url>.+) (?<code>\d+) (?<tail>.+)", RegexOptions.Compiled);

DataColumn ip1 = new DataColumn("IP Address");
DataColumn date1 = new DataColumn("Date");
DataColumn method1 = new DataColumn("Method");
DataColumn url1 = new DataColumn("URL");
DataColumn code1 = new DataColumn("Code");
DataColumn tail1 = new DataColumn("Tail");

ip1.DataType = System.Type.GetType("System.String");
date1.DataType = System.Type.GetType("System.String");
method1.DataType = System.Type.GetType("System.String");
url1.DataType = System.Type.GetType("System.String");
code1.DataType = System.Type.GetType("System.String");
tail1.DataType = System.Type.GetType("System.String");

dt.Columns.Add(ip1);
dt.Columns.Add(date1);
dt.Columns.Add(method1);
dt.Columns.Add(url1);
dt.Columns.Add(code1);
dt.Columns.Add(tail1);

using (StreamReader reader = new StreamReader(txtSource))
{
    while ((line = reader.ReadLine()) != null)
    {
        var match = ParseLineRegex.Match(line);
        if (match.Success)
        {
            //ip, date, method, url, code and tail - Parsing
            var ip = match.Groups["ip"].Value;
            var date = match.Groups["date"].Value;
            var method = match.Groups["method"].Value;
            var url = match.Groups["url"].Value;
            var code = match.Groups["code"].Value;
            var tail = match.Groups["tail"].Value;

            #region Viewing Purposes
            dr[ip1] = ip;
            dr[date1] = date;
            dr[method1] = method;
            dr[url1] = url;
            dr[code1] = code;
            dr[tail1] = tail;

            dt.Rows.Add(dr.ItemArray);
            #endregion

        }
    }
}