Adding a full html to a div

You can use Javascript:

<script>
  document.getElementById("demo").innerHTML = "Hello <b>world</b>!";
</script>

Or JQuery

$("button").click(function(){
  $("#demo").html("Hello <b>world</b>!");
});

You just need something that fires that event, for example a click and you can change it every time the event is executed. Your div should have the ID "demo"

<div id="demo">
  ...
</div>

You can also do this with php using include:

<div id="demo">
  <?php
    include("ruta_del_html.htmlophp");
  ?>
</div>

I hope it serves you.

You can use AJAX to read the contents of the other HTML file and write it to your page:

var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
    if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
        document.getElementById("ID_OBJETIVO").innerHTML = xmlhttp.responseText;
    }
}
xmlhttp.open("GET", "URL_DEL_HTML_QUE_QUIERES_LEER", true);
xmlhttp.send();

Or if you use a library like jQuery, you can do something even simpler with functions like $.ajax () or $.get():

$.ajax({
    type: "GET",
    url: "URL_DEL_HTML_QUE_QUIERES_LEER",
    success: function(datos) {
        $("#ID_OBJETIVO").html(datos);
    }
})

If the content is a Web page like GoogleMaps, as eduardo says, you should use an iframe (which is no longer recommended). Otherwise, if the Html code is inside your site, or is a partrialView you can do it using Jquery.

function insertHtml(){
$("#htmlins").html("<span>este codigo html fue insertado</span>")
};

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div id="htmlins">
 </div>
<input type="button" value="Insertar Html" onclick="insertHtml()"/>